This article claims that battery prices in China are already below the figure that Goldman Sachs expects by 2030:
The prices of lithium iron phosphate (LFP) batteries in China have decreased by 51 percent over the past year. The average price per kilowatt-hour has fallen to $53, compared to the global average of $95 per kilowatt-hour last year, according to Bloomberg.
$53 per kwh is roughly $3000 for a typical, small battery (50-60 kwh).