P&ID Question - Changing Diameter, Expansion, Contraction in Pipes

Hello, I am new to using P&ID diagrams, but I have to create one for an electric vehicle cooling system I created for a project in school. I was wondering if there are any symbols to indicate expansion or contraction in piping.

Another question I had was regarding elbows, but I believe elbows are not specified on a P&ID diagram.

I have to put 25 battery packs in parallel with parallel piping to all. Is there a proper way to indicate this without having to put all 25 in the diagram?
Work details for on battery pack as a separate pid, then on the master show the valve takeoff's (A through Y) that refer to the detail of each pack.