Electric cars: New cell chemistry for the Tesla Model Y

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Tesla will offer the Model Y with new cell chemistry in the battery packs. This is reported by Chinese media. From the fourth quarter of this year, the Model Y SUV with 72 kWh energy content from LFMP cells will be on the market. It is unclear when and if this variant will be available to order in Germany.

LFMP stands for lithium iron manganese phosphate. This composition is a further development of the LFP (lithium iron phosphate) cell chemistry that is for sale in the Model 3 sedan. The supplier is CATL, the largest battery supplier in the world. More than a third of all battery cells currently come from CATL, where the M3P designation is used for the new type. What can LFMP do?

The structure of most cells that are combined into traction batteries for electric cars in a system is similar. Graphite is used almost exclusively as the anode material. In some electric cars, a small amount of silicon is mixed with the graphite. At the cathode, on the other hand, there are significant differences. In Germany, a mixture of the metals nickel, cobalt and manganese (NCM) is the most common. NCM cathodes have a particularly good energy density; thus, a relatively large amount of electricity can be stored and released per litre of installation space and per kilogramme of weight.

LFP cells on the rise

Many electric cars are designed around the battery. There is a lot of space between the axles. So much that a reasonable range can be achieved even with cells with a lower energy density. The expensive cathode materials nickel and cobalt are therefore no longer automatically the first choice.

The best example of this is Tesla: the basic version of the Model 3, which unlike at the beginning (back then: Standard Range Plus) no longer bears a name suffix and does without the all-wheel drive Dual Drive, uses low-cost LFP cells with iron and phosphate at the cathode. The range of 491 instead of 602 km in the Model 3 Long Range is less - but a price difference of almost 10,000 euros (currently 49,990 instead of 59,490 euros according to the configurator) is a serious argument.

In addition, LFP cells are very durable and insensitive: The feared thermal runaway is unlikely. One downside, however, is the charging behaviour at sub-zero temperatures. Here, the electrical energy at the charging station is used at the beginning to bring the cells to their optimal operating temperature.

The low costs clearly speak in favour of further spreading LFP cells. The energy density not necessarily, which could become important especially for electric cars with less space between the axles. In other words, in vehicle segments that are below the Model Y, but where customers still want a good range.

LFMP: More range, same price

"LFMP cells would lead to improved range in electric cars such as the VW ID.3 or the Opel Corsa-e at reasonable cost," says Prof. Dr Markus Hölzle. He heads the Electrochemical Energy Technologies department at the ZSW (Centre for Solar Energy and Hydrogen Research Baden-Württemberg). Previously, Hölzle was responsible for product development for battery materials at BASF.

LFP can be chemically expanded to LFMP, explains Hölzle. By partially replacing iron with manganese, the cell voltage increases. This increases the energy density and indirectly the range. Although the charging and discharging capacity decreases at the same time, this is not the main issue for most electric cars anyway: "The challenge in production is to incorporate the manganese precisely into the structure. Otherwise, stability and durability suffer." LFP is a good-natured robust material, while LFMP is sensitive: LFMP is demanding in both production and processing.

Innovative strength at Tesla and CATL

CATL obviously has the confidence to do so. Professor Hölzle estimates that the energy density of LFMP cells is about 20 percent higher than of LFP cells. Although this does not come close to NCM cells, it is an attractive combination when cost and characteristics are weighed up.

Once again, the collaboration between CATL as a supplier and Tesla as a carmaker is proving to be innovative. As of today, there is no rear-wheel-drive entry-level variant for the Model Y as there is for the Model 3. Current reports say that competitor BYD will supply the blade battery with LFP cells to Grünheide. LFMP cells from CATL would be an ideal complement - or the toughest competition.

(pavb)