What is a Lithium Iron Phosphate (LiFePO4) Battery: Properties, Advantages & Alternatives
If you’re looking for a way to store electricity there are many ways you can do it. Anyone looking for a battery for their caravan, motorhome, home solar system, or boat could feel completely overwhelmed by all the options. Being faced with such a choice makes it difficult to decide which battery is best for you.
In this post, we’re exploring one of the latest advancements in lithium iron phosphate battery technology, the LiFePO4. Yes, it’s a type of Lithium battery, but it’s so much more than that.
What is a Lithium Iron Phosphate (LiFePO4) battery?
A LiFePO4 battery is a type of rechargeable lithium-ion battery that uses iron phosphate (FePO4) as the cathode material.
LiFePO4 stands for lithium iron phosphate battery, or LFP battery. You may be under the belief that all other lithium batteries are the same, but that is not strictly true.
Compared to other lithium batteries and lead acid batteries, LiFePO4 batteries have a longer lifespan, are extremely safe, require no maintenance, better charge efficiency, and improved discharge. They might not be the cheapest lithium ion batteries solution, but they are a smart investment.
For the average man or woman on the street, it appears that there are only a very limited range of lithium solutions. The most common are built using:
- Lithium Cobalt Oxide (LiCoO2)
- Lithium Nickel Cobalt Aluminium Oxide (LiNiCoAlO2)
- Lithium Manganese Oxide (LiMn2O4)
- Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2 or NMC)
- Lithium Iron Phosphate (LiFePO4)
Coming up we’ll explore the differences between the LiFePO4 battery and standard lithium ion battery. In addition, we’ll look at the history of lithium iron phosphate (LiFePO4) batteries, their benefits, and for the more technical amongst you, we’ll examine the more technical aspects of lithium iron phosphate battery technology.
What is the difference between lithium ion batteries and LiFePO4 batteries?
Lithium batteries have a wealth of applications, from wearable devices such as watches through to electric vehicles, electric tools, and medical equipment.
Compared to other lithium-ion batteries, the LiFePO4 has a lower energy density. This feature makes it unsuitable for small electronic devices but the perfect match for Rvs, bass boats, golf carts, electric motorcycles, and solar energy systems.
Before we look at the differences, let’s look at what makes them similar. Both battery types operate using a similar principle. The lithium ion the batteries contain moves between the positive and negative electrode to discharge and charge.
Another similarity is that they are both rechargeable batteries. Finally, both use graphitic carbon electrodes with a metallic backing as the anode.
Now time for the differences:
- Different makeup, chemically: You’ve probably already noticed this, thanks to their different names. A lithium ion battery will usually have a lithium manganese oxide or a lithium cobalt dioxide cathode. A lithium iron phosphate (LiFePO4) battery is made using lithium iron phosphate (LiFePO4) as the cathode. One thing worth noticing with regards to the chemical makeup is that lithium iron phosphate is a nontoxic material, whereas LiCoO2 is hazardous in nature. This factor makes their disposal a big concern for users and manufacturers.
- Newer technology: The technology used in lithium iron phosphate batteries is new than lithium-ion batteries. It has much better chemical and thermal stability. It is less likely to be combustible than a lithium-ion battery, even if you handle it incorrectly.
- Different life cycles: You can expect a much longer life cycle with phosphate chemistry. Both batteries already have a fairly long life span. However, lithium iron batteries are more stable if overcharged or short circuited, making them more long-lasting.
Short History of LiFePo4 batteries
Lithium batteries have been around for about 25 years. During that period, lithium technologies underwent an upsurge in popularity when it comes to powering small electronic devices such as cell phones and laptops.
However, you may remember several stories regarding lithium ion batteries that caught fire. For many years, this was the main reason their popularity didn’t extend to the creation of large battery banks and associated applications.
The issue of low electrical conductivity was overcome by reducing the size of the particles or coating them in a conductive material. Carbon nanotubes were a popular choice. Another way the issue was overcome was by doping lithium iron phosphate with cations of aluminium, zirconium, and niobium.
Once the issue of low conductivity had been ironed out lithium iron phosphate batteries became the answer to many people’s prayers. This new type of lithium batteries is taking the world by storm for many reasons. For example:
- LiFePO4 batteries are inherently non-combustible
- LiFePO4 batteries are safer
- LiFePO4 batteries come with many benefits that are perfect for high power applications
- Lithium Iron Phosphate batteries have a slightly lower energy density
Technical Specifications of Lithium Iron Phosphate batteries
Property | Value |
---|---|
Energy density | 140 Wh/L (504 kJ/L) to 330 Wh/L (1188 kJ/L) |
Specific energy | 90 Wh/kg (> 320 J/g) – 160 Wh/kg (580 J/g) |
Power-to-weight-ratio | 250-670 W/kg |
Lifespan (years) | 5-15 years |
Cycle life | >2000 cycles, up to 10,000, depending on conditions |
Nominal cell voltage | 3.2-3.3 V |
Charge time | 1-4 hours, depending on the charger |
Operating temperature range | -20°C to 60°C |
Self-discharge rate | 1-3% per month |
Minimum discharge voltage | 2.5 V |
Depth of discharge | 80%, 98% theoritical |
Safety | Low risk of thermal runaway |
Cost | £160-£800 per kWh |
Toxicity | Non-toxic |
Environmental impact | Low carbon footprint |
Capacity fade | Minimal |
State-of-charge accuracy | Good |
High-temperature performance | Less affected than other lithium chemistries |
Low-temperature performance | Reduced capacity below -20°C |
Are Lithium Iron Phosphate batteries deep-cycle?
Lithium iron phosphate batteries have the ability to deep cycle but at the same time maintain stable performance. A deep-cycle is a battery that’s designed to produce steady power output over an extended period of time, discharging the battery significantly. At that point, the battery must be recharged to complete the cycle.
This makes LFP batteries an ideal solution for deep cycle leisure applications that require energy over extended periods, especially when they are only charged occasionally, such as solar and off-grid applications.
What are the Benefits of Lithium Iron Phosphate batteries?
LiFePO4 batteries are a new type of lithium ion technology that uses lithium iron phosphate as the positive electrode material. They are becoming an increasingly popular type of lithium battery for the following reasons:
- High discharging and charging efficiency: Charge and discharge efficiency can reach as much as 90%, compared to only 80% for lead-acid batteries.
- High safety performance: Stable construction that doesn’t decompose, heat up or collapse like other lithium ion battery materials.
- Long battery life cycle: Has a life cycle of over 2,000 times compared to 300 times for long-life lead acid batteries. Theoretically, it could last between 7 and 8 years.
- Performs well at temperatures: The LiFiPO4 battery performs well at extremes of temperature with an operating range of -20C to +75C. Heating peak can reach 350°C-500°C
- High capacity battery: Compared to lead acid batteries and other lithium-ion batteries, the LiFiPO4 battery has a much larger capacity of between 5AH and 1000AH.
- Zero memory effect: LiFiPO4 batteries have no memory effect, unlike other rechargeable batteries.
- Lightweight: A LiFePO4 battery weighs one third that of lead-acid batteries.
- Environmentally-friendly battery: Generally considered free of rare and heavy metals, non-polluting, non-toxic, and in compliance with European RoHS requirements.
Is LiFePO4 better than lithium-ion batteries?
There are several factors that make LiFePO4 better than lithium-ion when it comes to batteries.
To start with, the cycle life of a LiFePO4 is much greater than a lithium battery, by more than four times.
In addition, LiFePO4 is the safest lithium battery type currently on the market. In terms of safety, it far exceeds lithium ion.
Another feature that makes them better is that they can reach 100% DOD or depth of discharge. What this means for the user is that they don’t have to stress over discharging the battery. Moreover, a quality LiFePO4 battery has a much longer lifespan. It’s rated at around 5,000 cycles, which is roughly 10 years. Over time, the average cost is also much better.
Are LiFePO4 batteries better than all non-lithium batteries?
It’s not just lithium batteries that fail to live up to the efficiency and effectiveness of lithium iron phosphate batteries. LiFePO4 batteries are better than all other battery types in general.
Stable, Safe Lithium Chemistries
When it comes to batteries, safety is an important issue. You may have read several news stories about lithium-ion laptop batteries exploding, for example, which of course is a little worrying.
The issue doesn’t arise with lithium iron phosphate batteries because they have the safest lithium chemistry. Its structural and thermal stability levels can be matched by other types of battery, including lead acid. It can withstand higher temperatures without fear of decomposing and is incombustible. It keeps cool at standard room temperatures and is not at risk of thermal runaway.
Exposing a lithium iron phosphate battery to extreme temperatures, short circuiting, a crash, or similar hazardous events won’t cause the battery to explode or catch fire.
This fact alone can be of great comfort for people who choose to use deep cycle lithium iron phosphate batteries on a daily basis in their scooter, bass boat, liftgate, or RV. .
Environmentally Safe
LiFePO4 batteries already have a big tick in the environmental box because they are rechargeable batteries. But that’s not all when it comes to their eco-friendliness. LiFePO4 batteries don’t leak, are non-toxic, and recyclable.
Excellent Performance and Efficiency
LiFePO4 batteries have an excellent reputation when it comes to performance and efficiency. Here are some stats to explain:
- They reach a full charge in two hours and sometimes even less.
- Self-discharge rate is a mere 2% per month, compared to lead acid batteries which are 30%.
- Compared with other lithium-ion and lead acid batteries, runtime is much higher.
- Power is consistent even when the battery life is below 50%.
- Zero maintenance.
Lightweight and Small
LiFePO4 batteries weigh almost 50% less than lithium manganese oxide batteries. They weigh 70% less than lead acid batteries.
What this means for the user who has one in a vehicle is less fuel consumption and better manoeuvrability. Also, their small size means you’ll have more free space on your boat, scooter, or RV.
LiFePO4 vs. Lead Acid Batteries
There’s no denying that lead acid batteries are a much cheaper outlay initially, however, in the long run, you’ll end up paying more. With lead acid batteries, you need to factor in the cost of maintenance and frequent replacement.
LiFePO4 vs. Gel Batteries
Gel batteries are similar to LiFePO4 batteries in that they don’t need to be recharged as frequently as other types of battery. In addition, they don’t lose charge when not in use. The main difference between these types of batteries is that gel batteries are very slow when it comes to recharging. You also need to make sure that you disconnect them as soon as they are 100% charged to avoid damaging them.
LiFePO4 vs. AGM Batteries
AGM batteries will make a huge dent in your wallet and the risk of damaging them when they are drained past 50% capacity is massive. Maintenance can also be very challenging.
LiFePO4 vs. NMC Batteries
Considering factors like cycle life, depth of discharge, and cost per kWh, LFP batteries are the better choice by leaps and bounds. However, which battery will be better for you can vary depending on the usage you require. Check our guide for a more in-depth comparison of lithium NMS vs. LiFePO4 batteries.
What are the different applications and uses of Lithium Iron Phosphate batteries?
LiFePO4 batteries have proven to be beneficial for a wide range of applications, for example:
- Solar systems: Because they are lightweight, you can haul them wherever you need to set up a solar system, even if its at the top of a mountain and far away from civilisation.
- Kayaks and fishing boats: You can enjoy more time out on the water because they have a longer runtime and lower charging time. Less weight on your boat also means it will be more manoeuvrable and able to move quickly.
- Commercial applications: LiFePO4 batteries have a wealth of commercial applications because they are so safe and tough.
- Mobility scooters and mopeds: You don’t have to charge them fully if you just want to make an impromptu trip.
LiFePO4 batteries can also be used to power electronic cigarettes, emergency lighting, flashlights, radio equipment, and more.
Can you use a Lithium Iron Phosphate battery in a car?
In most cases, LiFePO4 batteries work as a direct replacement for lead acid batteries, without any changes needed to the vehicle system settings.
Can I use a Lithium Phosphate battery as a starter battery?
LiFePO4 batteries have only been around since 1996 but they have become the most common choice for lithium starter batteries.
Are LiFePO4 batteries safe?
LiFePO4 are the safest type of lithium battery because they are not prone to overheating and even if they’re punctured, they won’t catch on fire. The cathode material is also non-hazardous and therefore it poses no environmental or negative health hazards.
Can LiFePO4 batteries explode?
Generally, lithium iron phosphate batteries do not explode or ignite. They are safer in normal use than other lithium or lead acid batteries, but can be dangerous in some extreme cases.
How long do Lithium Iron Phosphate batteries last?
Lithium iron phosphate batteries have a life of up to 5,000 cycles at 80% depth of discharge, without decreasing in performance. The life expectancy of a LFP battery is approximately five to seven years.
Are LifePO4 batteries better for the environment?
Compared to other lithium battery technologies, LiFePO4 batteries use more abundant and non-toxic materials that can be produced with less energy, so they are much better for the environment.
How to choose Lithium Iron Phosphate batteries?
When it comes to choosing lithium iron phosphate batteries, you want to look for a reliable provider that offers quality LiFePO4 batteries for a variety of applications.
Eco Tree Lithium is one such provider. We are a reputable UK lithium lifepo4 batteries specialist that sources the best lithium cells that have been technically designed in Europe. These cells provide the best performance and longevity. Additionally, Eco Tree Lithium offers a full 6 years’ manufacturer’s warranty againsts cell defects.
Conclusion
Batteries and battery power have become a key part of our everyday lives, but they come with human and environmental costs.
They are widely used in smartphones and laptops, and are also the beating heart of electric vehicles and much else. In addition, they help power the world’s electric grids, because renewable sources such as solar and wind energy, still can’t provide energy 24/7.
Nevertheless, LiFePO4 batteries are a step in the right direction, and we should be embracing the technology wherever possible.
FAQs
1. Do Lithium Iron Phosphate batteries need a special charger?
No, there is no need for a special charger for lithium iron phosphate batteries, however, you are less likely to damage the LiFePO4 battery if you use a lithium iron phosphate battery charger. It will be programmed with the appropriate voltage limits.
2. How much can you discharge Lithium Iron batteries?
LiFePO4 batteries can be continually discharged to 100% DOD and there is no long term effect. However, it is recommended that you only discharge down to 80% to maintain a lithium iron phosphate battery properly.
3. At what voltage is a LiFePO4 battery dead?
The low-voltage cutoff of most 12V LiFePO4 batteries is around 10 volts.