IMPORTANT: Many people & professionals don't know the difference between Lithium-iron & Lithium-ion Battery Technology, Lithium-ion is Inferior & more Dangerous Battery technology when it comes to Exploding & Catching on Fire (called Thermal Runaway).
LiFePO4 batteries are also called LFP Batteries and are similar to Li-ion, however LFP batteries have significant advantages that make them the ideal option for consumer-grade backup power solutions, LFP batteries are safe to install indoors, unlike Li-ion batteries that should Not even be charged indoors!
How do the Chemistries of LiFePO4 & Li-ion Batteries Differ ?
YES, LiFePo4 and Li-ion batteries are both rechargeable batteries that use lithium ions to harness and release electrical energy. While they are similar in many ways, they also exhibit some glaring differences.
Lithium-Iron Phosphate Batteries (LiFePO4 or LPF)
LiFePO4 batteries are a subtype of lithium-ion batteries that utilise unique chemistry to provide advantages over related lithium technologies. They have become increasingly Common in OFF-Grid and backup power solutions for our DART Micro Power Grids.
LiFePO4 get their name from the chemical composition of the cathode, which consists of lithium iron phosphate. The anode is typically carbon, the electrolyte is a lithium salt in an organic solvent.
The chemistry of LiFePO4 provides enhanced safety features compared to lithium-ion. The presence of iron, phosphorous, and oxygen atoms in the cathode creates strong covalent bonds. The result is that LiFePO4 batteries is more Stable, and less prone to thermal runaway  and overheating issues.
Crucially, LiFePO4 batteries do not use nickel or cobalt — two metals in dwindling supply and often questionably sourced.
Lithium-ion & Lithium-Iron Chemistry
Both Lithium-ion & lithium iron phosphate (LiFePO4) batteries comprise a variety of chemical compositions, including lithium manganese oxide (LMO), and lithium cobalt oxide (LiCoO2).
Both batteries have three essential components: a Cathode, an Anode, and an Electrolyte.
The Electrolyte for these batteries is lithium salt, whereas the Anode is carbon.
The Cathode is where the chemistries differ—they consist of one of the lithium metal oxides that give them their respective names.
The charging and discharging processes are the same for both of these. As the lithium ions move from the cathode to the anode, the electrons migrate in the opposite direction. This movement creates an electrical current.
What are the Comparisons ?
Safety
LiFePO4 batteries are a lot Safer than Li-ion due to the strong covalent bonds between the iron, phosphorus, and oxygen atoms in the cathode. The bonds make them more stable and less prone to thermal runaway and overheating, issues that have led to lithium-ion batteries having a reputation for a higher risk of battery fires.
Stability is why LiFePO4 Batteries are the standard in OFF-Grid and solar power applications. When the batteries are in the home, there is no room for error concerning overheating and other issues. Homeowners can confidently store their LiFePO4 battery in the house without worrying about fire safety issues.
Energy Density
Li-ion batteries typically have a higher energy density than LiFePO4. The energy density of a battery is a measure of how much energy it can store per unit of volume or weight. Li-ion batteries can store more power per volume or weight unit than LFP’s.
For example, the energy density of a typical Li-ion battery is around 100-265Wh per kg (45–120Wh per lb), while the energy density of a LiFePO4 battery is about 90-120Wh per kg (40–55Wh per lb). The expansive energy density range of Li-ion batteries is due to this statistic encompassing all types of Li-ion batteries, including technologies only suitable for electric cars and other applications.
For OFF-Grid power solutions, LiFePO4 remains superior in Safety, even when considering the slightly lower energy density, that difference is negligible as you move into larger stationary power solutions. For instance, this 6kW Portable Power Stations is set-and-forget battery solutions.
Weight
The weight of a battery bank has some correlation to energy density, as mentioned above. LiFePO4 battery banks may weigh slightly more than comparable Li-ion batteries, while some LFP’s may be lighter because the metals used in their construction are lighter.
Either way, any slight variation in weight pales in light of the other enormous advantages of LiFePO4.
Li-ion batteries with higher energy densities—such as nickel-cobalt-aluminium (NCA) and nickel-cobalt-manganese (NCM)—are no longer considered ideal for off-grid and solar applications. Instead, home power solutions use safer, longer-lasting technologies like LiFePO4. A safer battery is more important than a slight difference in weight.
LiFePO4 batteries are incredibly light, considering how much power they pack. This 6kW Portable Power Stations contains a 5.37kWh of energy storage, and weighs only 75kg — light enough to comfortably wheel around the house or toss in the back of a vehicle.
Temperature Range
LiFePO4 batteries offer a wider operating temperature range. They can function well in temperatures ranging from -20°C (-4°F) to as high as 60°C (140°F).
In contrast, Li-ion batteries have a much smaller temperature range of 0°C (32°F) to 45°C (113°F). Users need to store Li-ion batteries in climate-controlled spaces during the depths of winter or the heat of summer.
LiFePO4 batteries are safe to store in the house, shed, garage, or other indoor space without air conditioning. They're less susceptible to temperature changes, giving you more options for locating the battery without potential damage or reduced efficiency.
Lifespan
Many Li-ion batteries can go through around 500 charge and discharge cycles before degrading in performance. LiFePO4 batteries can go through thousands of cycles before their performance begins to drop.
For example, this Portable Solar Power Station have a charge cycle rating of 6'000 cycles (16+ Years) before it reaches 50% capacity. Smaller options tend to have lower lifespans, as smaller Power Station will commonly be Discharged lower, which may only provide a cycle life rating of 80%+ capacity after 3000 cycles (8+ Years).
However, that is still a reliable lifespan. After this time, the battery will still function at a minimum of 80% of the original capacity. Even after this slight drop in performance, you may still receive years of use from your LiFePO4 battery bank!
This much longer lifespan means that LiFePO4 will reduce the environmental impact resulting from e-waste. The lack of nickel and cobalt also makes them more environmentally friendly.
You can use your LiFePO4 battery bank for 5 or 6 times longer than a Li-ion model, and you won't waste money on replacements.
Cost
The cost per watt-hour of LiFePO4 and Li-ion batteries can vary wildly depending on the manufacturer, market demand, and capacity. LiFePO4 batteries don't use nickel or cobalt, materials that can fluctuate dramatically in supply and price.
LiFePO4 is now a more common battery chemistry, meaning there more manufacturers and supply, which makes LiFePO4 batteries more affordable, in 2023 Residential LiFePO4 modules are down to $500 per kWh, and Commercial 200+ kWh ins explosive proof Cabernet are now down to $385per kWh.
Even if there is a slightly higher cost than comparable Li-ion battery packs, the advantages of LiFePO4 outweigh the price difference. Any extra costs go toward added safety, longer lifespan, and other benefits.
Self-Discharge Rate
LiFePO4 batteries have a self-discharge rate of around 1-3% per month, depending on usage, temperature, and other factors. The low self-discharge rate means you can leave the battery in storage for months, it will still supply substantial power even after a period of disuse.
Self-Discharge is a Non event if used in a Micro Grid, as the batteries should be Charged every Day.
Voltage
LiFePO4 battery Cells have a lower nominal voltage than Li-ion batteries, typically around 3.2V per cell, compared to Li-ion with 3.6V to 3.7V per battery cell.
The voltage can impact the design of battery packs and the voltage requirements of devices that use them, however 48~51.2VDC is now common voltage for Residential Power, with Commercial Hi-Voltage configuration going from 380VDC ~ 1'000VDC and higher. |
