Since I retired in 2008, technology may have moved on. What I recall was li-ion batteries were a nightmare.
Failures were, thankfully, rare but when they occurred they could be very bad. At a guess I would say 1 in 150000 failed. This does not sound too bad, but how many are out there in laptops and other devices? I know of at least one person who had her flat totally destroyed when she was charging a li-ion battery pack.
If abused, the batteries can catch fire and explode. For this reason I never ever leave li-ion batteries charging unattended. Assume they are potential bombs.
See https://www.bbc.co.uk/news/av/world-us-canada-63532906 .
I am sure many incidents in the past were brushed under the carpet as product recalls could be extremely expensive.
These batteries can be misused. Treat them with the greatest respect.
