Today, mainly two types of chemical composition of Li-Ion cells, LFP and NMC, are used in electromobility. The first one is more ecological (doesn’t have nickel or cobalt), has higher durability and resistance, is usually a little cheaper, on the other hand, it has low energy density and worse resistance to cold. The NMC is the opposite. Companies Farasis Energy nevertheless managed to develop such NMC cells that retain their advantages, but at the same time solve some of their disadvantages. The result is the P73 and P75 cells, which have densities typical of NMC, but surpass many LFPs in terms of lifetime.
In the case of articles P73 these are high density models. She does here 285 Wh/kg, which is higher than most electric cars today. The charging speed was such that it took 30 minutes from 10 to 80%, then the discharge was at 1.8C. This ran from 93% to 3% at 35°C (so not 100% to 0%, which is normally considered a cycle). The result was that the batteries retained around 82-83% of their original capacity after 5000 charging cycles. The drop was fairly linear, so 80% of the original capacity could be reached after 5700 charge cycles, assuming the same drop. If such an accumulator were in a car with a range of 400 km and was operated in that 90% range (that is, 360 km), its lifespan would be over 1.8 million km, if we consider reaching the 80% limit as the end of its lifespan.
At the same time, only 1% of cars drive over 320 thousand km during their entire lifetime. After 320 thousand km (less than 1000 cycles), the battery still had 95% of its original capacity, i.e. a range of 342 km from the original 360 (applies when using 90% of the range, otherwise 380 km from 400). At the same time, NMCs usually have a lifetime of 500-2000 cycles, LFPs are usually around 4000 cycles.
Articles P75 are aimed at faster charging. It took a shorter 20 minutes to go from 10 to 80%, however the discharge was in the 97% to 5% range at a slower 1C rate. These batteries have a slightly lower energy density 270 Wh/kg, which is still quite a nice number, especially considering the lifespan, which should exceed 15 years. The test took place at a temperature of 25 °C. Here, over 84% of the original capacity was reached after 5000 cycles, so 80% would be reached after about 6300 cycles. For cars with a paper range of 400 km, we would be talking about a service life of almost 2.1 million km.
The company cooperates with the Mercedes-Benz car manufacturers or the Chinese company Voyah (the luxury division of the Dongfeng brand). In the case of Mercedes, they are planned to be deployed not only in passenger cars, but also in heavy electric trucks. The above-mentioned accumulators are already in mass production. Also working on cells for electric aircraft, where Farasis is preparing models with a lifetime of 10,000 cycles.
Source: www.svethardware.cz
