Lithium Iron Phosphate, the “new” kid on the battery block?!
There is no doubt that lithium-ion batteries have been a constant source of discussion, especially as we see the energy storage market evolve. With a current market value of $50 billion, we’re seeing a time of accelerated growth. Interestingly this growth is accompanied with the rise of alternatives to the classical high energy Li-Ion battery materials.
However, we also know that this growth comes with its own set of issues. Efficient battery recycling is still a challenge, as is balancing performance and cost at a larger scale.
But where is the market heading?
While we’re not exactly fortune-tellers (it would be easier, though!), the revival of lithium iron phosphate (LFP) cathode material signifies that change is coming.
Do we value high performance? Or is it affordability and secure supply (abundance)? That’s the real question we’ll explore. Like always in life: “There is no free lunch.”
The current state of LFP batteries
LFP batteries aren’t exactly new to the scene, but they haven’t really been considered as an option for EVs and stationary storage just recently. LFP batteries do have some advantages that could prove beneficial in the future, and the big players are starting to take note.
Contemporary Amperex Technology Co Ltd (CATL), one of the dominant battery makers, recently signed an agreement with the local government in the Sichuan province to build an LFP cathode materials plant. Their investment totals to about $280 million, signaling the intent to shore up supply as the demand for lithium batteries increases. And guess who was their first customer — Tesla. Like so often, one step ahead of the game. Why LFP?
So why is the market moving towards LFP cathode material? Well, we can think of a few reasons.
One of the most significant advantages of LFP battery chemistry is that it does not contain cobalt. As we’ve explored in a previous article, potential cobalt shortages have been a concern in scaling battery technology so that LFP could be a way around this issue. Plus, LFP is cheaper to manufacture overall, which is a big draw for businesses looking for affordable battery options as they scale.
The other major advantage is safety. LFP has an extremely safe battery chemistry, as cells do not burn or explode. That also negates the need for any protective material, so it’s a cost-efficient option without compromising safety. Rather surprisingly, safety plays a key role in China, which lead to a massive rise in LFP powered vehicles, especially buses in China — representing the biggest market for EV’s. According to Interact Analysis, 2018 already 95% of all electric buses in China were LFP powered.
China’s CATL has plans to take this technology even further. In a recent announcement they revealed that LFP cathodes will be an essential part of their solid-state battery production. This would open a whole new playing field for the LFP chemistry.
The downside of LFP?
But of course, we can’t talk about the good without touching on the not-so-good. While LFP seems like a viable alternative against many of the future issues the industry is facing, it does have its cons. Unfortunately, a lot of it does relate to performance.
For businesses that are looking to favor performance over safety and material concerns, LFP may not be the best option. Not only is it lower voltage, but it also has a lower energy density, only approx. 65% compared to high energy Nickel-Cobalt-Manganese-Oxide (NCM) materials. Although it might not seem like a dealbreaker now, customers may not be pleased with the trade-off, especially as there is already a demand for quick and minimal charging time.
Another issue that one needs to deal with when using LFP batteries, is their particular voltage profile — the shape of the charge and discharge curves. Whereas in materials like NCM, one can observe a positive / negative slope for the charge or discharge respectively, the voltage profile for LFP is extremely flat (Figure 2).
This is a challenge for the Battery Management System (BMS). The BMS classically uses the voltage profile to calculate the state of charge (SOC) and state of health (SOH) of a battery. For example when using NCM, the SOC at 3.7V is higher than at 3.6V, hence more energy is still available. For LFP materials, this is not so easy, since almost the entire charge/discharge is happening at around 3.4V, resulting in a lower accuracy of LFP-based BMS.
Outlook?
LFP comes with pro’s and con’s like every cell chemistry. However it has some tremendous advantages that convinced the EV super power China to go down that road. With Tesla and VW following, the stage is set for the revival of LFP.
The coming years will show if we really need 600 km in range in EV’s… or if that’s an old philosophy, inherited from gasoline car times. The question is: “What are the most important KPI’s for the majority of applications?” Is it really high-performance? Or can most applications live with the likes of LFP’s — leaving the big-boost batteries for the Porsche Taycans of this world.
