BATTERY LOWER CASING AND BATTERY SYSTEM

The disclosure relates to a battery lower casing (1) and a battery system. The battery lower casing includes: a bottom plate (14); a plurality of fixing beams (11) sequentially connected end to end and fixed to the bottom plate; a cross beam (12) disposed between the oppositely disposed fixing beams; and a supporting bracket (13) including a base plate (131) and limiting portions (132), wherein the limiting portions are connected to the base plate and disposed opposite to each other, the base plate and the oppositely disposed limiting portions enclose and form a recess (133), the base plate is connected to the fixing beam and an end portion of the cross beam adjacent to the fixing beam is embedded in the recess such that the cross beam is connected to the fixing beam.