I've investigated mishaps involving batteries for a long time and was the 787 Airworthiness investigator. Lithium batteries have now been in production for 30 years, so not quite a new technology anymore. While there are all sorts of lithium batteries on the market, the ONLY battery chemistry to install lithium based batteries in a boat is LiFePo4 with a BMS (battery management system). Stay away from any of the chemistries which have cobalt, as when it misbehaves, it is more energetic and capable of fire. Battleborn and the other name brands are all well tested and have great safety histories but they are expensive.
Great resource for anything lithium &/or solar:
https://www.mobile-solarpower.com and his Youtube channel:
https://www.youtube.com/channel/UCoj6RxIAQq8kmJme-5dnN0Q
Diversion for a related subject:
We all have carry-on lithium batteries such as power tools, cameras, laptops, jump packs, vapes, etc. Since we consumers have no idea what the chemistry is and consumer products don't have a great history (apparently includes Conception dive boat fire), treat all carry-on batteries as having the potential to overheat at any time. Random factoid of the day: Of the lithium battery related fires in airplanes (it's common), more than half are spare batteries!
Have a way to (1) control any flame or smoke until (2) you quickly pitch them overboard. These two steps are mandatory because the smoke can quickly overcome you in a cabin, you can not put out a lithium battery fire, and the flame or radiant heat has a history of igniting things nearby such as wood, fabric, and foam (which releases cyanide gas when burning). The answer to (1) and (2) are actually quite simple.
First is to simply have a couple of inexpensive fire blankets (fiberglass) to cover overheating batteries and control where the flames go. Example:
https://www.amazon.com/Tonyko®-Fibe...ords=fire+blanket&qid=1583512698&sr=8-10&th=1
Second is when not in use and especially when charging, to keep batteries or devices in a steel case (loosely wrapped in a small fire blanket in the sink would work too) that does NOT have a tight fitting top. Use something to loosely separate individual ones to prevent physical damage. Ammo boxes are great for this. Do NOT latch the top tight to prevent pressure from building which can make the box burst.
I can be reached thru my website at:
www.HowItBroke.com
Bob