how the battery behaves in this diagram

how the battery behaves in this diagram

My question is this. I'm using this ic mppt SM72445 along with a 250 watt solar panel, mppt output configured to 50.4 or 51 volts, 12-cell lithium-ion battery pack and bms, if the load is less than the output of mppt the battery will be charged, but what happens when the load is greater than the mppt output and there is a voltage difference between the mppt output and the battery? example ; mppt output = 50.4V 5A / battery pack = 46.8V 3.9Vcell * 12 / load = 10A my doubts are for the difference in voltage between the two sources, mppt and battery in parallel

There won't be any difference, the mppt output will be pulled down to the voltage of the battery - as it will under all conditions. Even without any load at all, if the batteries are only partially charged the mppt voltage will be down at the same voltage as the batteries. That's how it's supposed to work.