You will find that every seller has "grade A brand new" cells for sale.
Very, very, few actually do (automotive grade) and those that do send you the test reports from EVE.
Do you need automotive grade for solar storage? No. However as I pointed out, what you actually receive is a real crapshoot. If you get decent bulk grade cells (not used and already end of life capacity wise) and don't try to use them as high amp (either charge or discharge) you will be happy due to the price difference. Unfortunately, you don't have any clue why they failed. One of the steps is to X-Ray the cell to make sure that there are no sharp edges on the jelly roll that might cause an internal short. That scares me, although one would hope that EVE is ethical and won't sale dangerous cells.............. Maybe.
All of the true automotive grade that I've purchased (32 so far) have exceeded both watt hours and amp hour ratings. All of the cells I have received that were not automotive grade (16) tested below rated capacity. Some as low as 264AH (for a 280AH cell). After almost 3 years, the grade B cells still perform without significant degradation (so far, and I check). Which you should get depends on your budget and risk tolerance. I can afford the true automotive grade, so that's all I purchase now. Amy from Shenzen Luyuan is where I purchase mine.
Shenzhen Luyuan Technology Co., Ltd., Experts in Manufacturing and Exporting Lifepo4 battery, LTO battery and 0 more Products.
szluyuan.en.alibaba.com
I have been extremely happy with the 304AH cells.