Lithium iron phosphate cells have long led a shadowy existence in the automotive sector. However, a rethink is currently taking place. Why this is the case and why LFP cells are becoming more and more established.
Lithium iron phosphate batteries are cheap and robust. What future do they have in electric vehicles?
Black_Kira / Getty Images / iStock
Various materials can be used in battery cells. Lithium-ion battery cells based on nickel, manganese and cobalt (NMC) are currently the most commonly used cell chemistry. However, the alternative cell chemistry of lithium, iron and phosphate, i.e. lithium iron phosphate (LFP), is also coming to the fore. And LMFP batteries, which use traditional LFP with the addition of manganese, could soon become established. What is behind the trend towards LFP cells?
The LFP cell is a lithium-ion cell. However, lithium iron phosphate is used as the cathode, which means that LFP cells cannot keep up with NMC batteries in terms of range and charging performance. For this reason, they "were not considered for automotive use [for a long time] because the system has a lower energy capacity compared to the other Li-ion chemistries", explains Richard Backhaus in the ATZ article Cell Developments for the Batteries of Future Electric Vehicles. According to a report by the PEM Chair at RWTH, current LFP cells have an energy density of around 200 Wh/kg, says Backhaus. This is around 20 % less than comparable Li-ion cells.
High Safety and Low Costs
However, this disadvantage is offset by two advantages in particular: high safety and low costs. Backhaus writes: "However, supply problems and cost increases for Li-ion raw materials have led to a rethink, as the materials for LFP cells are readily available worldwide". LFP-based batteries do not require the critical raw materials nickel, manganese and cobalt and are therefore not subject to the high price fluctuations of cobalt and nickel. LFP-based batteries are generally around 20 % cheaper to manufacture than lithium-ion batteries with the same energy capacity.
LFP cells also score highly in terms of safety. They are "very safe since they do not catch fire and at the same time have a long lifetime of over 2000 cycles. The latter is also the reason why these batteries are particularly suitable for bi-directional charging", says Ursel Willrett from IAV in the MTZ interview "For cost reasons, it does not make sense to design the networks for maximum demand".
LFP is also coming into focus due to the trend towards cell-to-pack, "as the lower energy density at the cell level is compensated by the higher packing density of the cells in the battery pack", explain Alexander Kohs and Robin Brachtendorf from Bertrandt in the ATZ article Cell-to-pack - Potentials of Compact Battery Design along the Lifecycle. "Due to their low price, as well as their high level of safety, durability, and absence of critical materials such as nickel and cobalt, LFP cells have a positive impact compared to NMC cells both economically, ecologically, and socially on the entire battery system," the authors summarize.
Tesla and BYD are Leading the Way
The pioneers in LFP cells are the US electric car manufacturer Tesla and the Chinese electric car manufacturer BYD. "In the meantime, however, other companies are also using LFP cells, or are planning to do so", says Backhaus. Volkswagen, for example, has declared its intention to offer LFP batteries for the entry-level segment of its vehicle range. According to media reports, Nissan is also considering equipping electric cars produced for emerging markets with cheaper LFP cells from 2026. BMW is also working on the further development of energy storage systems. Sixth-generation storage technology also offers the option of using cathodes made from LFP for the first time. In addition, the affordable small electric cars based around the Citroën ë-C3 will have an LFP battery. The LFP battery supplied by Svolt has a capacity of 44 kWh.
According to their advantages and disadvantages, NMC and nickel cobalt alumina (NCA) technologies on the one hand and LFP cells on the other are used in vehicles: "In electric vehicles, where achievable speed and the ability to drive longer distances are prioritized over price (upper class segment), NMC and NCA technologies seem to be more popular due to their higher performance. If price is the top priority, LFP-based batteries are used, for example, for larger vehicles such as buses or heavy-duty transport or for small vehicles," says the Fraunhofer Institute for Systems and Innovation Research (ISI). In Europe and the USA, the high-performance and more expensive luxury vehicles are particularly well represented on the market, while in China there are also many small cars with LFP cell chemistry.
Development Towards LMFP
Optimizations of LFP cells are primarily aimed at increasing the energy density. For example, the energy density of an LFP cathode can be increased with the help of manganese (LMFP cathode). Further developments of the LFP cell therefore focus on adding up to 75 % manganese to the lithium iron phosphate. "This results in an increase in cell voltage from the current 3.2 to 3.3 V to more than 4 V, thus compensating for the disadvantages compared to other cell chemistries," Backhaus quotes Dr. Kai-Christian Möller from the Fraunhofer Battery Alliance. However, the challenge here is that the ion conductivity in the cathode is sufficiently high and the material remains stable despite the high manganese content.
CATL is taking a different approach with the so-called M3P cell, says Backhaus. Here, iron is apparently partially replaced by metals such as magnesium, zinc or aluminum in the olivine structure of the LFP. According to CATL, the cell should therefore offer 10 to 20 % more energy density than conventional LFP cells.
China Currently Dominates NMC and LFP Production
According to the Fraunhofer ISI, the global production of batteries with LFP cathodes mainly takes place in China, where it accounts for just over a third of total battery production. In contrast, the production of battery cells with NMC cathodes would account for just over a quarter in China. By 2030, Chinese production is expected to account for around a quarter of total global production of NMC cathodes.
According to the Fraunhofer ISI, NMC and NCA cell production dominates in the USA. This corresponds to around half of total production there. The USA's share of global production of cells with NMC cathodes is only expected to reach around 20 % by 2030. LFP cell production in the USA is relatively low and therefore only accounts for a small proportion of global production.
According to the Fraunhofer researchers, the production of NMC battery cells will clearly predominate in Europe by 2030. Over the course of the coming decade, European NMC battery cell production will therefore also account for an increasingly relevant share. At the same time, LFP cell production in Europe should also slowly increase and become more relevant. However, China currently dominates both NMC and LFP battery cell production. However, if "the announcements in Europe are actually implemented at the targeted rate, NMC battery cell production in Europe would even be larger than in China by 2030", it says.
This is a partly automated translation of this German article.