I would say Chinese LFP cells are of decent quality, but not great - one thing that definitely needs improvement is the rigidity of the cell casings. The cells tend to swell during heavy use, especially in hot climates and all of the manufacturers require the use of metal plates and straps to restrain this swelling. Unfortunately, having to keep the cells bundled up with the manufacturer's strapping makes it a lot harder to find spots to install them in a vehicle. The end user has no choice but to break the bundles apart and then figure out how to repackage them so they won't swell. This, to me, is totally unacceptable because once the cells start to swell a vicious cycle ensues: the internal resistance increases rapidly with swelling which causes the cells to heat up more which causes more swelling, etc.
Additionally, the datasheets for all of the Chinese LFP cell manufacturers are poor. Some don't even include good dimensional data and even worse is that the manufacturers often change the dimensions of the cells without warning or even updating the datasheet (if it had dimensional data in the first place).
Internal resistance of the cells, even those in the same "batch", can vary wildly. I have personally found a 2:1 variation in cells by recording the difference in voltage drop when rapidly switching back and forth between a 1C and 2C load.
One good thing I will say is that cell capacity (in Amp-Hours) is almost always accurate.
Overall, it does appear that Chinese LFP cells are improving and that bodes well for the future.
It would definitely be nice if they were more widely available in the US.
