How did the Chinese battery producer solve the low energy density in lithium iron phosphate (LFP) batteries?
Frequent readers of InsideEVs probably remember when CATL and Tesla signed a battery supply agreement. It was on February 3, and that led CATL to be one of the three battery suppliers Tesla currently has. Besides Panasonic, LG will also sell to the American EV manufacturer. Now Reuters reports that the companies are discussing the supply of a cobalt-free battery, which would bring environmental, compliance, and financial benefits to Tesla.
Gallery: Tesla May Buy CATL’s Cobalt-Free Cells
These batteries use lithium iron phosphate chemistry. These batteries are considered to be much better than lithium-ion cells in most aspects. They last longer, don't catch fire, have a constant voltage while discharging, and the lack of cobalt makes them much cheaper. Their handicap is the low energy density, which explains why you probably have never seen an EV with them.
These talks between Tesla and CATL probably include new developments the Chinese company has made to this sort of batteries. Has it managed to give them a higher energy density? It is worth remembering that both Jason Fenske, from the Engineering Explained YouTube channel, and Bill Gates have recently pointed low energy density in lithium-ion batteries as one of the main issues EVs currently have.
One of the possibilities for that is the cell-to-pack – or CTP – technology CATL released in September 2019. It is a similar concept to the one Obrist has adopted with its vacuum fixation technology. Instead of integrating the cells into a module and then into a pack, the cells can be directly integrated into the pack. That reduces the mass and increases the energy density.
According to CATL, that makes battery packs have 40 percent fewer parts and reach a mass-energy density up to 15 percent higher.
CATL claims to currently have lithium-ion batteries that can achieve 240 Wh/kg, and it plans to take them to 350 Wh/kg in 2024. The best LFP cells have an energy density of 160 Wh/kg, which would lead the company to offer a 184 Wh/kg battery with the CTP technology, still below that of its present lithium-ion cells.
After having a look at the Chinese company's website, we have seen it may also offer its LFP cells with EnerSpeed, a solution that makes them charge faster. CATL says the "fast ionic ring" and the "super electronic network" would allow lithium ions to move more quickly, providing a 300 km range in 15 minutes.
Apart from avoiding the human cost of God-knows-how cobalt mining, the LFP battery would also be cheaper than current batteries used in EVs by a "double-digit percent." Yes, it could be 10 percent, but any cost saving in a massive-scale industry is worth celebrating – as long as it does not affect the product's quality level.
Will this CATL deal be included in the Tesla Battery Day? Which technologies can this new cell adopt to get closer to the energy density lithium-ion batteries present? Would they allow for a simpler and less expensive management system? So many questions and just a distant perspective for answers, right? We'll eventually get there.