Smartphones, laptops, electric cars, energy storage solutions… And always, at the heart of these products, a battery. In the small world of autonomous electric products, Tesla plays a central role, through the impetus that its cars have given to the electric revolution, but also in that of scientific research relating to batteries.
A dedicated research center supported by a specialist in the sector
Thus, if Panasonic played an essential role in the manufacture of Tesla’s batteries, Elon Musk’s company is working upstream on research in this area. Since June 2016, the Californian firm has created a dedicated center in Canada. the Tesla Advanced Battery Research is the result of a partnership, signed in June 2015, with Dalhousie University in Nova Scotia. Of course, the choice of this university owes nothing to chance. It counts among its professors and researchers, a certain Jeff Dahn, world-renowned pioneer of lithium-ion batteries.
Over the years, with his teams of researchers and students, he has focused on two essential aspects: energy density, i.e. the quantity of electricity that can be stored, which makes it possible to reduce the size of batteries for a same autonomy, and the longevity of the cells.
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A new step forward
In the Journal of the Electromechanical Societya specialized scientific journal, Jeff Dahn, Michael Metzger and other researchers have published a new article, simply titled Li[Ni0.5Mn0.3Co0.2]O2 as a Superior Alternative to LiFePO4 for Long-Lived Low Voltage Li-Ion Cells.
They describe work, co-financed by Tesla, which resulted in a battery using materials different from lithium-iron-phosphate accumulators (LiFePO4, or LFP). The latter have gradually taken over in many cases of use, since their introduction in the mid-1990s. These solutions indeed offer a high density and a long life, as well as a deep cycling capacity, which allows its use for energy storage.
In addition to Lithium, Jeff Dahn’s teams used nickel, manganese, and cobalt (and graphite, of course), at a low voltage, around 3.8 V. The conclusions of their experiments, with these cells called NMC532, are very promising.
First of all, at temperatures of 40, 55 and even 70°C, the energy density of their battery is higher than that of the cells of an LFP battery. Then, their number of life cycles is also higher. While the energy efficiency – in other words the coulombic efficiency and the voltage efficiency – is much better, the losses during charging and discharging, including passive ones, are reduced.
Very encouraging findings
Simulations of the use of these batteries have made it possible to establish that the energy cells retain a high energy retention capacity, despite a large number of cycles. These results are impressive enough for the researchers to indicate that at an operating temperature of 25°C, these accumulators could see their lifespan exceed one hundred years. The key seems to be in the use of a lithium salt based electrolyte (LiFSI), very common in lithium-ion batteries.
This durability could reduce the need for battery renewal and thus solve one of the most worrying ecological aspects in the multiplication of batteries to power devices or store energy.
Moreover, the researchers indicate that these advantages could also apply to other accumulators using nickel, including those which use little or no cobalt. This rare material, also called the blue metal, is indeed at the heart of conflicts and exploitation of local populations, including children, particularly in the Democratic Republic of Congo.
The potential to change things
Obviously, it will always take some time between the scientific demonstration, which has just been made, and the daily application of this research. Nevertheless, these new “batteries” have many virtues, their higher energy density than that of LFP cells could make it possible to replace this technology when it reaches its limits, or when the initial cost is less important for the successful completion of the project than durability. storage.
Similarly, and this is the next step that Jeff Dahn’s teams will be looking at, these batteries could be adapted to fast charging.
Without it being indicated what Tesla could do with it, one can imagine that its Powerwall, its domestic units, or the gigantic electric energy storage farms, like those which it manufactured in Australia, would be potential candidates.
At a time when one of the major challenges is to decarbonize our energy, and therefore to be able to resolve the issue of sustainable energy storage, the production of which is uncertain, this new, greener and more enduring approach seems encouraging.
Source : Journal of The Electrochemical Society via Electrek