Welcome to CD!
In the past our team has used a variety of different ways to mount and secure our battery. We usually build an aluminum box around the battery so it doesn't wiggle or move around.Then to secure the battery in the box we use seatbelt material.
The first year (2011) we used seatbelt material we sewed velcro onto it, worked quite well until we has some accidental discharge and the rivets pulled out of the seatbelt.
In 2012 we learned from the discharge and used the seatbelt material as well as a
cobra buckle instead of the velcro. We also doubled up and reinforced the rivets holding the belt.
Last year we went back to velcro but the name brand stuff. We again used the seatbelt and just used one continuous piece around the whole battery box so we could eliminate the weak point of the rivets.
Overall if there is any doubt in your mind about it coming out or breaking the holder the battery is seated in, it can never hurt to reinforce it more. Also make sure it is easy to release the battery and take out. You don't want to be dealing with zip ties or complicated systems if you have a quick back to back match.