FWIW I'll share some observations after doing some shopping (but not yet buying).
(1) After someone posted informative videos about testing and grade A vs. grade B, I will certainly NOT accept any cells on which the QR code has been obliterated as was the case on the cells Expresso just received, especially after his measured capacity was less than advertised. That supplier is now crossed out in my spreadsheet.
(2) Although some companies such as BLS say that they are manufacturers, and they may be in one sense or another, they do not manufacture these cells. At most they do the aging, testing, drilling and tapping and packaging for retail sales.
(3) BLS offers two different 200 Ah cells.
The ones with the rectangular posts are 1C suggested discharge rate and 1C maximum continuous discharge rate.
https://blslifepo4battery.com/collections/100-200ah-lifepo4-battery/products/grade-a-3-2v-200ah-lithium-iron-phosphate-lifepo4-battery?variant=32514206072912 I have not bothered to try to figure out who actually manufactures these cells. They are cheaper than the other ones with the round posts in square bosses.
The "round post in square boss" 202 Ahr cells are not made by BLS, but by CALD, the largest battery manufacturer in China and among the world's largest, with factories in at least China, Germany and the U.S. (those are joint ventures with BMW and Tesla - but, who owns what percentage of what is hard or impossible to figure out, they are not exactly transparent about corporate arrangements). What probably explains the higher price is that they are normal discharge rate = 1C, but maximum continuous discharge rate = 3C.
https://blslifepo4battery.com/collections/100-200ah-lifepo4-battery/products/3-2v-200ah-lifepo4-battery?variant=32511661637712(4) A given supplier may sell the same batteries at different prices via different channels. Here's the BLSStore AliExpress listing for the 202 AHr round post cells:
https://it.aliexpress.com/item/33019962665.html?spm=a2g0o.store_home.productList_132779083.subject_6 Delivered price to Italy for 8 cells = $1,443.95. (Shipped to the U.S. would be about $70 less, I suppose because Italy's 22% VAT is higher than the U.S. excise tax on batteries.)
Here's the same battery at BLS's own web pages:
https://blslifepo4battery.com/collections/100-200ah-lifepo4-battery/products/3-2v-200ah-lifepo4-battery?variant=32511661572176 Delivered to Italy for $1,358.00.
And at Alibaba, there are two listings for the same cells with a $1 per cell difference in price:
https://www.alibaba.com/product-detail/3-2V-200AH-LiFePO4-Battery-Prismatic_1600142382534.html?spm=a2700.shop_pl.41413.18.6bbd4022X8NA3O Delivered to Italy for $1,086.00 and
https://www.alibaba.com/product-detail/Factory-price-US-Europe-stock-CATL_1600150734810.html?spm=a2700.shop_pl.41413.26.1d9440229FEjPb for $1,078.00 (Again, $70 less for shipment to the U.S. rather than Italy) In other words, the same batteries from the same supplier cost $45 per cell more on AliExpress than on Alibaba.
And, via Alibaba the rectangular connection batteries would come to $1,038.00 ($40 less for 8 than the round post batteries):
https://www.alibaba.com/product-detail/Grade-A-NEW-3-2V-200Ah_1600142191594.html?spm=a2700.shop_pl.41413.14.6bbd4022X8NA3OOf course, these are today's prices - tomorrow's will probably be different.