Conventional lithium-ion batteries, those with nickel-manganese-cobalt (NMC) chemistry, remain the most popular on the market. But others are making rapid inroads, establishing themselves as an increasingly credible alternative. In particular, progress with lithium iron phosphate (LFP) batteries is impressive.
LFP batteries work in the same way as lithium-ion batteries: they too have an anode and a cathode, a separator and an electrolyte, and they use the passage of lithium ions between the two electrodes during charge and discharge cycles.
What changes are the materials used for the various components, which are cheaper and more readily available. Of course, there are advantages, but there are also disadvantages. But first a bit of history.
From China to the rest of the world
LFP batteries were developed in the 1990s as an alternative to the lithium-ion batteries that won their inventors the Nobel Prize in Chemistry. They attracted interest for several reasons: they were cheap, non-toxic and used iron, a very common material. However, they also had poor electrical conductivity, making them unsuitable for many applications.
LFP battery in a Tesla Model 3
By working on the internal architecture and covering the cathodes (the cells composed of lithium, iron and phosphate) with different conductive materials, they were able to overcome this obstacle and improve performance.
Today, China is the biggest producer of this type of battery and also the biggest user. In fact, many low-cost electric cars produced in the country already use LFP batteries. But this technology is also rapidly gaining ground in Western countries. Not least because the industry is making great strides and the gap with lithium-ion batteries is closing.
LFP batteries: the advantages
In addition to the economic advantages($100/kWh compared with $160/kWh for NMC batteries) and the availability of raw materials, LFP batteries are preferable for other reasons. Firstly, they last longer. They can often exceed 10,000 charge and discharge cycles without compromising performance too much (lithium-ion batteries go up to around 3,000 cycles and are then generally used for purposes other than use in electric cars).
Battery production at the Svolt factory
They are also safer because they are less flammable and more resistant to heat, and they can release energy more quickly because they have less internal resistance. Finally, they can also be completely discharged without suffering major damage.
LFP battery: disadvantages
On the other hand, as already mentioned, LFP batteries have a lower energy density than NMC batteries. This means that they have to be larger and heavier to guarantee equivalent autonomy. Or, for the same size and mass, they can cover a shorter distance between charging points.
But the difference is diminishing. Whereas in the past, the reduction could be as much as 70%, it is now only 20 to 25%, and even less with the latest-generation products. Svolt has an LFP battery that reaches 200 Wh/kg, while CATL has one that exceeds 160 Wh/kg.
The battery in the entry-level version of the Volvo EX30 will be of the LFP type.
There are two other problems: LFP batteries have a lower voltage (3.2 V compared with 3.7 V) and they generally recharge more slowly. However, with regard to the latter, some of the latest-generation products achieve charging speeds equal to those of 'normal' lithium-ion batteries. For example, Zeekr, a brand of the Geely group, has presented the Golden Brick, a battery that will reach the market in 2024 and whose active material represents more than 80% of the total. According to the company, it will provide 217 miles (350 kilometres) of range in just 10 minutes of stopping at the charging station.
Everyone wants one
As we have seen, China invested earlier and more than others in this type of battery (which was already on the market before the pandemic). It did so because, more than other countries, it felt the need to lower the price of its electric cars to encourage sales. BYD, for example, has introduced its Blade battery, which adopts LFP chemistry, but many manufacturers offer similar products. NIO, JAC, GAC, and even the major battery manufacturers, starting with CATL, have such products in their catalogues.
Whereas in the past, LFP batteries were almost exclusively "from China for China", things are changing rapidly today. Tesla, for example, uses this type of battery for the entry-level versions of the Model 3 and Model Y. The same strategy applies to Volvo, Hyundai, Stellantis and Ford, to name but a few.
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