Short-circuit current ESS

We have built a 3x5000 MultiPlus system with LFP batteries — an ESS (Energy Storage System).
In off-grid (emergency) operation, the system delivers insufficient short-circuit current to trip a B16 circuit breaker.
What is the solution for this?

Maybe a C-curve breaker will work? I only use RCD’s on the output have never just used a breaker.