What is a LiFePO4 Battery? A Technical Overview

Nowadays, our lives are too dependent on batteries, as they help us charge and run most of our devices or appliances, such as mobile phones, laptops, digital cameras, fans, refrigerators, microwaves, light bulbs, and more. With advancements in the battery field, today's market offers many batteries, including LiFePO4, lithium-ion, nickel-cadmium, and more.

LiFePO4 battery has taken the battery world by storm. Recently, it has become one of the most popular and trusted rechargeable batteries due to its longer life and a range of other unique features. If you want to explore this battery's specifications in detail, read the discussion below.

What is a LiFePO4 battery?

A battery made with lithium iron phosphate is commonly called a LiFePO4 battery. It is also known as an LFP battery. Some other batteries that belong to the lithium family include lithium-ion, lithium titanate, lithium cobalt oxide, and lithium nickel cobalt aluminum oxide.

Lithium iron phosphate (LiFePO4) batteries are considered the most reliable, safest, most environmentally friendly, and most stable lithium batteries. In comparison to lithium-ion batteries, LiFePO4 batteries last longer and are safer to use in various conditions.

A Lithium iron phosphate batteries has 100% discharge capacity (no need to worry about over-discharging) and delivers high power density. This battery is an ideal choice for applications where short bursts of high power are required because it can deliver high currents for a shorter period.

The common applications of LiFePO4 batteries include electric motors, home appliances, and energy-hungry devices. They have started replacing lithium-ion batteries in solar-powered equipment like Solar RV Kit, and General Off-Grid Solar Kit.

How do LiFePO4 batteries work?

The working principle of lithium iron phosphate batteries is quite similar to traditional lithium-ion (Li-ion) batteries. In both battery types, lithium ions move between the anode and the cathode for charging and discharging purposes. These batteries use lithium iron phosphate as the cathode and graphite carbon as the anode material.

When a LiFePO4 battery is connected to a battery charger, lithium ions travel from the cathode (lithium iron phosphate crystal) to the anode (graphite crystal) and embed themselves in the graphite lattice. Exactly the opposite happens in the case of discharging.

When your battery is connected to the load, it starts to discharge. Lithium ions re-intercalate into the lattice during the discharging process, as they move from anode (graphite crystal) to cathode (lithium iron phosphate).

Lithium iron phosphate batteries have various safety mechanisms, making them more reliable for outdoor and indoor applications. These mechanisms include solid electrolytes, thermal runaway prevention, stable cathode material, battery management system, non-flammable electrolyte, and explosion-proof casing. Moreover, LiFePO4 batteries operate efficiently when you place them in the ideal temperature range of 0-45 degrees Celsius (or 32-113 Fahrenheit).

Key applications of LiFePO4 batteries

Lithium iron phosphate batteries offer a wide range of real-life applications for running various devices (like portable electronics and electric vehicles) and developing reliable backup power sources to deal with frequent power outages.

1. Renewable energy: LiFePO4 batteries are used in different renewable energy systems. They help you store excess energy and deliver a consistent power supply. For example, they can store excess solar energy during the daytime and provide it at night or when the utility grid is off. Similarly, these batteries can store excess energy from wind farms and can be combined with other energy sources to offer a reliable power supply.
2. Electric vehicles: Lithium iron phosphate batteries are lightweight and have higher specific energy. Therefore, they are the perfect power source for EVs, as they reduce the vehicles' overall weight.
3. Portable electronics: These batteries have high energy density, are compact and lightweight, and deliver high current over shorter periods. Therefore, they are an ideal choice for portable electronics, such as power banks, mobiles, and laptops.
4. Backup power systems: Due to their safe operation, longer lifespan, and high energy density, LiFePO4 batteries are perfect for backup power systems with uninterruptible power supplies and solar electric systems.

Benefits of LiFePO4 batteries

Behind the increasing demand for LiFePO4 batteries, there is a long list of advantages they offer. Let's explore some of them.

1. Lifespan

Lithium iron phosphate batteries last longer than conventional lead-acid and lithium-ion batteries. You can charge and discharge these batteries from 2,500 to 5,000 times before they lose 20% of their total capacity. In contrast, the efficiency and capacity of lead-acid batteries are reduced after they are charged a few hundred times.

2. Safety

LiFePO4 batteries come with greater protection against thermal runaway and overheating; therefore, they are safer than Li-ion batteries. Moreover, the risk of explosion or catching fire is much lower with lithium iron phosphate batteries. This is why they are frequently used in residential applications. Unlike lead-acid batteries, LiFePO4 batteries don't emit harmful gasses.

3. Environmental benefits

They are made with non-toxic materials and are fully recyclable. In addition, they lose minimum energy during the charging and discharging processes. Lithium iron phosphate batteries also reduce waste and hazardous greenhouse gasses. Moreover, they contribute to cleaning up the air. Further, they reduce dependency on fossil fuels.

4. Efficiency

The efficiency of LiFePO4 batteries is incomparable to lithium-ion and lead-acid batteries. When it comes to charging, lithium iron phosphate batteries hold the full charge within just 2 hours or even less. Their self-discharge rate is only 2% per month when they are not in use, which is 30% for lead-acid batteries. Moreover, they have a higher runtime than other lithium batteries or lead-acid batteries.

5. Temperature sensitivity

LiFePO4 batteries can function properly in extremely low and high temperatures, unlike lithium-ion batteries. For example, a lithium iron phosphate battery can work seamlessly on as high as 60°C (or 140°F) and as low as 20°C (or -4°F).

LiFePO4 vs. Lithium ion batteries

Now that you are familiar with LiFePO4 batteries, how they work, and what benefits they offer, Let's now compare these batteries with Li-ion batteries to see which one performs better.

1. Energy density

The energy density of Li-ion batteries is higher than LiFePO4 batteries, which is why a lithium iron phosphate battery is not a great choice for wearable devices such as fitness trackers, smart watches, and AR glasses. But, LiFePO4 batteries are the best choice for EVs, boats, RVs, and solar electric systems.

2. Safety

Lithium iron phosphate material has better structural and thermal stability. Therefore, LiFePO4 batteries are safer than lithium-ion and any other lithium batteries. Moreover, lithium iron phosphate batteries can withstand higher temperature levels without decomposing. They stay cool at room temperature and are not prone to thermal runaway.

3. Cost

Apparently, the cost of lithium iron phosphate batteries is much higher than lithium-ion batteries. Since LiFePO4 batteries last longer than Li-ion batteries, they are affordable for long-term uses. More importantly, the higher cost is due to the incorporation of added safety features.

4. Durability

Lithium iron phosphate batteries are more durable than their Li-ion alternatives. Lithium-ion batteries can last for 300-500 cycles, whereas LiFePO4 batteries can last for up to 5,000 charge-discharge cycles. In terms of years, Li-ion can only last for 2 to 3 years, whereas LiFePO4 batteries can last for around 10 years.

LiFePO4 batteries vs. Non-lithium batteries

This section compares lithium iron phosphate batteries with non-lithium batteries, such as nickel-cadmium (NiCd) and lead-acid batteries.

1. Weight

Lithium iron phosphate batteries have higher energy capacity for a given mass than nickel-cadmium batteries. Therefore, the weight of LiFePO4 batteries is lower than NiCd batteries. Similarly, LiFePO4 batteries have more lightweight structures than conventional lead-acid batteries. The weight of a LiFePO4 battery can be as low as half of the weight of a lead-acid battery of the same dimensions. This is why lithium iron phosphate batteries become the ideal choice, where weight and space are important.

2. Cost

The manufacturing cost of LiFePO4 batteries is lower than that of NiCd batteries. In terms of watt-hour, LiFePO4 costs around 20% more than nickel-cadmium batteries. On the other hand, lithium iron phosphate batteries are costly compared to lead-acid batteries. However, in the long run, LiFePO4 batteries will be more affordable than their lead-acid counterparts.

3. Efficiency

LiFePO4 batteries are more efficient than NiCd batteries in different ways, such as cycle life, energy density, temperature sensitivity, environmental impact, power savings, maintenance, etc. The energy density of a LiFePO4 battery is double that of a NiCd battery. Similarly, lithium iron phosphate batteries are more efficient than lead-acid batteries due to their higher round-trip and charging efficiency.

Best lithium iron phosphate battery

Below is a list of three top-performing LiFePO4 batteries and brands in the United States. Let's explore the products quickly.

1. Renogy 12V 100Ah LiFePO4 battery

It is manufactured with premium-quality battery cells that can last for more than 4,000 charge cycles. 100Ah Smart Lithium Iron Phosphate battery launched by Renogy comes with a dependable BMS system with dual processors. It uses BT-2 Bluetooth module to monitor data in real time.

2. Renogy 12.8V 100Ah LiFePO4 mini battery

It is the Renogy's smallest lithium iron phosphate battery. It comes with a low-temperature cut-off feature to ensure safe charging in freezing temperatures. You can monitor the battery stats by using it with a 300A battery shunt. Moreover, this battery is vibration-resistant and IP65-rated for an unmatched outdoor performance.

3. Renogy 12V 300Ah deep cycle LiFePO4 battery

It is known for delivering 59% more power than a 200Ah same-sized lithium iron phosphate battery. It offers low-temperature protection and supports series-parallel, parallel, or series connections. The self-heating feature makes this battery a perfect choice for all-weather living. 24-hour timely assistance and 5-year product warranty adds more value to the credibility of this battery.

Note: If you want to buy a new battery, ensure you consider its capacity, voltage/power ratings, lifespan, energy density, safety features, group size, weight, and size.

Conclusion

A LiFePO4 battery is the most stable, reliable, and long-lasting battery compared to all other lithium batteries available on the market, which is why it is rapidly replacing Li-ion batteries. It also performs better than non-lithium batteries like lead-acid and nickel-cadmium.

If you are wondering where you can use lithium iron phosphate batteries and why they have become so popular in the past few years, be sure to read the discussion above.

Frequently asked questions

Is LiFePO4 better than lithium?

Yes, LiFePO4 batteries are considered better than all other lithium batteries due to their higher stability, long life, low self-discharge ability, and enhanced safety.

Why is LiFePO4 so expensive?

Lithium iron phosphate batteries are costly due to their added safety features, the need for a battery management system, manufacturing approach, and of course raw materials.

How many years do LiFePO4 batteries last?

If you maintain them properly, these batteries can last between 5 and 10 years. Premium care can help your LiFePO4 batteries last for up to 10,000 charge cycles or even more.