Enough energy does not guarantee enough power
A 200 kWh battery with a system limited to 50 kW continuous output cannot be assumed to support a steady 100 kW load. A high-power system can also run out of energy quickly. Ask separately for nameplate energy, usable energy, continuous PCS output and any short-duration overload rating.
Check a simple load case
A constant 100 kW load running for two hours needs about 200 kWh at the load. That is not the final battery purchase size. Conversion losses, permitted depth of discharge, reserve and end-of-life capacity must be considered. Motor starting can introduce a separate power requirement. Compare proposals using the same assumptions.
Find the measurement boundary
Cell-level or DC-side figures are not directly comparable with energy delivered at the AC output. Request temperature, discharge rate and test conditions, and check whether continuous operation causes derating. The useful question is how much energy reaches the agreed load, under the agreed conditions, and for how long.
Further reading: sam.nrel.gov
This article supports early project discussions. Final configuration depends on site conditions.