this post was submitted on 18 Oct 2024
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[Dormant] Electric Vehicles
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Something to consider is that NMC and NCA cells can use less volatile electrolyte, with several solutions to that particular problem already existing in commercial applications. On top pf that, there are additives to electrode material that can physically separate them from their current collector, thus stopping all electrical flow completely. Panasonic is starting to produce such cells now.
LFP doesn't have a higher cycle life, it has an equal cycle life but with lower current capacity. So at the end of the cell's expected lifetime the LFP cell has stored and discharged vastly less Watt-hours than an NCA or NMC cell. This is a really critical component of the lifetime cost calculation, obviously.
LFP isn't a really good power source, it's an entirely acceptable power source. But in the application of a vehicle where weight is a key factor because road wear increases with the 3rd or 4th power of vehicle weight, any cell technology that requires a physically larger and heavier pack (LFP requires both dimensions be increased) isn't a clear win. LFP is a great technology for stationary storage, though, since the size and weight are much less of a concern.
One of the key things to remember is that any technology that improves one cell type is likely to improve all similar cell types. So as improvements in electrolyte and current collector safety improve with LFP, they also improve with NCA and NMC which makes the latter two more attractive.
In the recreational marine market, where fire is a beyond catastrophic event, everyone seems to have standardized on LFP for its safety characteristics. We're replacing lead-acid (mostly AGM or sealed deep-discharge variants) batteries anyway, so just going to anything lithium-based is already a huge improvement in terms of weight, volume and storage performance.
LFP in Marine applications is mostly a cost driven choice, because the cost per kWh is 10-20% lower for LFP compared to NCA and NMC. NCA and NMC batteries are absolutely available for marine applications, and they store around 33% more energy for the same volume as LFP which makes them a good choice in space constrained applications. But, as you pointed out most marine applications are converting from AGM which is so huge that any Lithium based battery is a win.
If fire safety was the determining factor, LTO would be the battery choice rather than LFP. But nobody's going to make that choice because LTO sucks compared to LFP.