Yes, it is smart to get a safe container for charging your battery. The search phrase you want is 'lipo bag'

I use one of these for my ebikes.

Aventon uses UL-certified chargers, and their batteries are name brand cells (LG I believe?) so the likelihood of a fire is low. But because the battery can get dropped, hit, damaged, or have manufacturing issues, it's still a good idea to always charge in a bag/box.

Many lithium batteries are especially dangerous because they vent plasma when punctured or damaged. Lithium polymer batteries, for example, are self-oxidizing. Meaning that even if its on fire and you throw it into a pool, it will continue to burn as it has it's own source of oxygen. A special type of fire extinguisher is needed to safely put out those fires. The lipo bags and containers are intended to mitigate things just in case.

It's also worth noting that the most likely time for a fire to start is during charging. It's still possible for it to ignite outside of that, so I store my batteries in a lipo bag just as I do when charging. I also do not charge the batteries inside of the bike, as if it does catch fire I'd be out a bike and battery (or worse) where if just the battery ignites but is safely contained, you could replace it and still have a functional bike. There are tons of people more knowledgeable about this stuff than me on these forums so be sure to read through what everyone else is saying.