Former CEO, LG Chem Power
Prabhakar has been at the forefront of the evolution in vehicle electrification for 40 years. Prabhakar is a trained aeronautical engineer and started his career at Ford where he worked his way to Chief Engineer of Hybrid Technologies which was the lead role on the Escape Hybrid, the first electric production programme by a North American OEM. After realising lithium-ion batteries were the future, Prabhakar left Ford in 2005 and joined as CEO of Compact Power which later became LG Chem, one of the largest battery manufacturers globally. Prabhakar currently advises various electric battery, technology, and vehicle start-ups. Read moreView Profile Page
Could you start by giving us a bit of a history into different types of chemistries and formats in EV batteries?
I think there’s really the three main ones that have been there since day one, day one being somewhere around 2005. The oldest is the cylindrical format, the 18650 as it’s commonly known, the 18mm diameter, 65mm height, used in consumer electronics. It used to be used in laptops, until laptops got too thin to accommodate it. But then Tesla and Panasonic have adopted it for vehicle use. That format is better suited for NCA chemistry, which is also something that Tesla and Panasonic have selected, so that’s a combination that works together, whereas the rest of us in the industry concluded that the better format was a flat format because the size of the cylindrical cells gets limited. You cannot make it too fat, otherwise you get too much temperature difference between the center and the surface of the cell. Plus, it involves more parts, so for various reasons, most of the vendors agree that it’s better to go for cells, make them as large as possible to cut down on the number of cells, which then reduces the overhead when you make them into a pack, in terms of the battery management, thermal management, et cetera.
So, the two predominant flat-formats, which is a rectangular footprint, are either pouch or prismatic: the pouch is basically where the active material in some sense is shrink-wrapped in the enclosure; whereas, in the case of prismatic, it is enclosed in a hard metal shell. But both of these formats cannot use NCA chemistry because of the gassing that it undergoes and the pressure changes, which is what the cylindrical cell can do, and that in some sense also means we use the NMC nickel-manganese-cobalt cathode composition chemistry. So that’s the brief history of these two major chemistries and these three formats. There’s also the LFP chemistry, lithium iron phosphate, which is something that was pushed originally by the Chinese government because it does have a little bit of a safety advantage, but it suffers from poor energy density — as much as maybe 20% compared to NMC — and as a result, for most passenger vehicle applications, NMC is the preferred chemistry. However, LFP will have its role, both in buses and stationary energy because of its advantage in safety because you can evacuate a personal car in a few seconds, a bus takes a minute, so the safety edge becomes important, and similarly, in stationary applications where the energy density doesn’t matter, so it will have its place. Plus, it does not use any cobalt, so for that reason, going forward, these three chemistries are going to be the dominant ones. NCA used by Tesla and Panasonic, NMC used by the rest of us, and then LFP for stationary and buses.
Why did Tesla choose the NCA chemistry?
Because it allowed them to get the lower cobalt faster than we could with NMC. Again, as you may recall, consumer electronics cells used to use pure cobalt, LCO, but that was bad for two reasons: toxicity of cobalt and cost of cobalt. So, we started, with vehicle application, using what’s called 333 or 111 equal-proportion nickel-manganese-cobalt and went to 532. Today, we’re at 622, which is 20% cobalt. The NCA is already below 10% and maybe closer to 6% to7% cobalt. However, Tesla had started with cylindrical cells, and there’s a bit of history behind that also. When Tesla started, none of us major battery manufacturers wanted to invest because Tesla was a question mark and was too risky an investment. But for cylindrical cells, there was a glut on the market because laptops had gotten thinner, and Panasonic actually had 40% to 50% overcapacity, so Tesla got a great deal on cylindrical cells. It was appropriate for NCA chemistry, so that combination has gone forward and now, because they put so much into making those cells work and doing a great job of system engineering on packs, they are going to stay with it for some time. However, if you fast forward as the market grows – and it may grow by a factor of ten by 2025 – and the majority of that is going to be NMC, which will then tip the scales in favor of NMC for economies of scale that Tesla had for some time. So, that’s going to change the cost equation in favor of NMC. It remains to be seen whether Tesla pivots over at some point to the flat format and NMC.
Where are we today on unique cost of the cell and the pack?
In major manufacturers for Western markets where you’re offering ten years of warranty, it’s about $120 a kilowatt/hour at the cell level and between $160 and $170 dollars a kilowatt/hour at the pack level.
That’s a total, you mean. So, $40 to $50 per kilowatt/hour for the pack? For the battery, for the systems around that, plus the cell cost, which is $120?
Right, so 75% of the pack cost is made up of cells and the rest is battery management system, thermal management system, and the manufacturing cost.