I'm probably just spamming the thread now, but I thought I'd give a quick summary of the evolution of EV batteries and where they're headed to show why I don't think battery life is an issue at all.
First up, a quick overview of Lithium ion batteries. As with all chemical battery cells, there's a Cathode and Anode (+ and -) seperated by a barrier that allows only lithium ions to pass through, with an electrolyte that the lithium ions are soluble in. The electrolyte is the organic part of the battery that actually burns when there's a battery fire.
Different Cathode chemistries will have different qualities. There are two main types:
-Ternary batteries have some mix of Lithium, Nickel, Manganese, and/or Cobalt in different ratios to give different attributes with regards to power output (think how quickly it can charge/discharge), energy density (how much room it taks up for the same amount of storage), and stability (thermal runway fires, heat output, degradation, etc). These batteries generally are much more sensitive to battery degradation, but better for vehicle performance.
-Lithium Iron Phosphate is much safer (very hard to start on fire), cheaper, and has a better degradation profile but is much less energy dense and therefore weighs more and takes up more space for the same amount of energy. It's mainly cheaper because China strategically poured their resources into the technology because they owned the supply chain for this technology and saw it as a way to dominate the market by making their preferred technology the cheaper and therefore most common one. It's much less sensitive to temperature and thermal runway, but less powerful so performance takes a bit of a hit.
Battery degradation is largely due to lithium metal forming dendrites on the anode which can puncture the barrier or cause shoirt circuits. This irreversibly damages the cell and leads to incremental loss of capacity over time. The most common reasons for these dendrites to form is fast charging, over charging and high temperature. Think of charging a battery like a filling an air tight container with water. As you get near the end you need a lot more pressure to squeeze that last bit in and it puts stress on the container. Keeping the battery always fully charged then will significantly increase dendrite formation so many EV manufacturers lock away some capacity. All hybrids do this and they go through a lot of full charge/discharge cycles. Newer ternary batteries have and expected life (to get to 80% of original capacity) of 1-3000 full cycles. this gives you some idea of how long these should last in the real world. Someone going from full to empty and back every single day would get about 2 to 9 years (or about before hitting 80%). No one really drives like that though so they should last much longer.
History:
The first real mass production EV was the Nissan Leaf and it debuted in 2010. It had a 117km range from an air cooled 24kWh battery that cost $1,200 per kWh to produce. This first generation only could charge at 3.3kW (ie every hour you're getting 3.3kWh) at home or 44kW at a CHAdeMO fast charger. The fast chargers were largely non-existent so charging was a bit of a nightmare. The other bad thing about this vehicle was that the chemistry was more prone to dendrite formation and had no active temperature management, just had airflow to cool it. As expected, there was significant battery degradation, especially in higher temperature areas like California, Arizona, etc. When you're starting with 117km range and you lose 20%, that's massive. There's used early Leafs still on the market with 50% range, sometimes even less. The head of Nissan just said that almost all their original batteries are still in their original cars, though I suspect their not really being used much with that low of range.
Next came Tesla with a newer NMC (nickel, manganese, cobalt) battery that had better performance and they used liquid cooling to increase the lifespan and performance of the battery. Many of these batteries are still in use with good capacity today. For example, there is a Tesla model S in Europe with 1,500,000 km that has only had two batteries (excluding a "loaner battery" for 95,000km after the first one). These batteries probably cost about $100 per kWh now for Tesla to produce and largely have no cobalt with just nickel and manganese.
The largest battery manufacturers in China were all in on LiFPO batteries and Tesla started putting them in all their Model 3's produced in China after their Gigafactory in Shanghai opened. They found that the performance wasn't too affected and the battery life was vastly improved while being significantly cheaper to make. They now use LiFPO for all Model 3's in China and Europe.
The Chinese manufacturers have made significant improvements in LiFPO batteries in the last couple years and now have much better densities and performance. CATL has found a way to incorporate manganese into LiFPO batteries to boost density by 15%. I think this is going to be the winning formula where LiFPO batteries see incremental improvments for most vehicles and NMC batteries are used for high performance vehicles. The holy grail is solid state batteries because they would use no flammable electrolyte and the density would much higher. Even if they solve it (which no one has been able to solve in a scalable way), it'll be a decade or more to see them used regularly. There are sodium ion batteries being worked on and many other chemistries, but none of them to date have shown the performance and scalability of Li ion batteries.
As for battery production, there's an absolutely massive and mind blowing build out. In 2010, global lithium ion production was 19GWh which was mainly used in consumer electronics. This year, the capacity is about 500Gwh. By 2030 that could be 6TWh or higher! I'm not sure most people have wrapped their heads around that absolutely massive number. The Inflation Reduction Act has spurred an even greater race to build baterry and mineral production in North America so that number may even grow.
I hope someone finds that a bit illuminating as to why battery life and perfomance will not be a reason EVs won't be better than ICE.
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