Lithium ion batteries are one big happy family. They all operate on the same general principles, but incorporate different elements. Understanding that basic concept makes the rest of the discussion on EV battery technology much easier!
Battery types tend to be named after the chemicals used in the cathode, which is what lithium ions flow towards when the battery is being used. The anode, where the ions of a charged battery are stored for use, is generally made of carbon or graphite, and despite research into new anode materials, there is not as much variation in current anodes.
Different batteries can prioritize either the life span, maximum current, or capacity of the pack. Depending on the use, a different chemistry may be used. For instance, batteries with manganese have very low internal resistance and can be charged pretty fast. However, these batteries tend to have shorter lifetimes.
For EV use, the more popular batteries are NMC (lithium nickel manganese cobalt oxide) and NCA (lithium nickel cobalt aluminum oxides), which combine metals with nickel and cobalt to make them last longer and hold more energy.
What Is An LFP Battery?
If you read EV news or have thought about getting a Tesla this year, you’ve come across the letters “L,” “F,” and “P.” LFP batteries are lithium ion phosphate, which is a highly stable but slightly less energy dense battery composition. What this means is that an LFP battery of the same size will hold slightly less energy than an NMC or NCA battery. If this is the case, why is there an industry-wide push towards LFP and away from cobalt configurations? Is this happening for all EVs, or are there particular use cases where one battery chemistry might be preferable?
The big headlines this year in terms of LFP batteries have been about Tesla – of course. Tesla announced in 2021 that they would be switching all Standard Range models to LFP battery chemistries.
LFP Batteries in Tesla Models
Tesla announced in October 2021 that it was switching to LFP batteries for its standard range models, both Model 3 and Model Y. The reason it kept the cobalt batteries for the Long Range trims is because of the lower energy density of LFP configurations – in order to get performance or very long range, you need a larger LFP battery.
The margins that make LFP work are very thin, and it is believed that they only work in Standard Range Teslas because they are engineered with efficiency in mind.
LFP Material Sourcing and Cost
The main argument for LFP batteries often boils down to material availability and cost. Initial sourcing concerns centered around cobalt, which is a rare earth metal that is often mined in areas known for conflict and human rights violations. Moving away from such a fraught source made sense ethically and for business continuity.
More recently, there has been a market shortage of nickel and aluminum, both of which are exported by Russia. Even prior to the invasion of Ukraine, businesses felt the sting of relying on materials with sensitive prices and sometimes hostile suppliers. On the other hand, phosphate is much easier to source and so far, are reliably cheaper. This means that LFP batteries can be much cheaper than cobalt-based batteries.
Price Impact on EV Batteries
The other reason that this battery change is happening for Tesla is because Standard Range models are designed to be more entry-level priced vehicles, meaning that the customers who want them may be less flexible about price increases due to battery costs. Unlike the target shopper for a Long Range or Performance model, the Standard Range shopper may be more impacted by a several-thousand-dollar price change.
LFP Battery Range and Charging Effects
It is true that LFP batteries lack some of the energy density that their NCM cousins offer. This means that the range of a Model 3 Standard Range Plus will depend on the battery chemistry. But, while the LFP battery offers 10 miles less in terms of EPA range, they do offer some consolation.
We all know that to keep a lithium ion battery healthy, it should not be charged to 100% every day. At Recurrent, we suggest charging to 80-85% for optimal lifetime. However, this wisdom applies mostly to NCA and NMC chemistry. Since LFP batteries are more stable, they can be charged to 100% for daily driving.
In fact, Tesla suggests charging your LFP Model 3 to 100% at least once a week to balance voltage and recalibrate range and charge readings. You can check the battery chemistry of your Model 3 by looking at the charge settings in the app – if the options include 50% and 100%, the vehicle has an LFP pack.
In effect, charging to 100% means that the usable range for an LFP powered Model 3 is the same as its EPA range, while the usable range for an NCA Model 3 is only around 90% of that. When you do the math, the LFP battery has a longer daily range.
Longer Cycle Life
One way that scientists talk about battery life is by “cycle lifetime,” or how many times a battery can be charged and then discharged before its capacity falls below 80% of original.
Several studies show that LFP batteries have a cycle life of 2 to 4 times longer than NMC batteries. However, with a slightly lower range, you might need the extra cycle life to achieve the same mileage as with a NCA or NCM pack. The higher cycle life is also part of the reason that Tesla recommends charging to 100%: you won’t even notice any additional battery degradation on an LFP.
EV Battery Safety
Although the risk of any lithium battery catching on fire is rare, highly publicized recalls for the Bolt and Kona have raised concerns about safety. LFP batteries have a much higher threshold for heat, which is what causes thermal runaway, or battery fires.
For LFP batteries, thermal runaway temperature is at 270 degrees C, as compared to 210 C for NMC and 150 C for NCA. While a car’s thermal management should protect from any battery getting this hot, LFP batteries do add a layer of protection.
Cold Weather Charging for LFP Batteries
LFP batteries sure sound great! However, there are some downsides to consider, most notably cold weather charging and range loss. The impact of temperature on EVs is nothing new, but some aspects are especially pronounced with LFP batteries.
Many drivers have been complaining about extremely long times for the battery to warm, severely reduced range, and slow charge times in cold weather. While preconditioning does resolve these issues, drivers who can’t always anticipate their cold weather trips will suffer.
In a video from November, 2021, Bjorn Nyland shows that performance doesn’t suffer, but charging speed definitely does, without preconditioning your LFP in cold weather. He posits that BMS updates to the SR+ Model 3 might have improved range and thermal management in the vehicle’s second winter on the road.
Lowering Operating Voltage
LFP batteries have a lower operating voltage per cell than other common lithium ion batteries, which means that you might need more of them if you need a specific voltage. As a reminder, voltage measures how much pressure drives the electrons from one electrode to the other, and thus, how much work can be done by a circuit.
This means that LFP technology is not a one-size-fits-all solution. For heavy transport needs, LFP may not be as useful as cobalt-based batteries, since a higher workload may be needed. Look no further than Tesla’s semi, which will use nickel-cobalt-aluminum based 4680 cells.
LFP Batteries Are Simply Heavier
Related to their lower energy density, LFP batteries often need to be bigger - and heavier - than their NCA or NMC cousins. This can reduce efficiency in an EV and possibly cause more wear on tires.
Will Your Next EV Have An LFP Battery?
This article is a long way of saying “maybe.” Here is a list of vehicle manufacturers that have either hinted at or promised using LFP in the future.