Article doesn't mention but says the company is BYD Energy Storage which apparenly uses
Lithium Iron Phosphate (LFP) battery technology (specifically, Lithium Iron Phosphate / LiFePO₄
The article says the batteries are sourced from BYD, and it's likely lithium iron phosphate batteries.
These ones are from BYD, however Poland is constructing another, smaller BESS in parallel where the batteries will be supplied by LG Energy Solution and manufactured near Wrocław, Poland.
> BYD Energy Storage will supply the battery technology.