They don't give a lot of details but battery powered items have been causing problems in a lot of applications. I just never considered a lawn mower where you would naturally plug it back in when done. I'll watch to see if they update with more details.
Exploding lawnmower burns down Maine home — Mid-Maine — Bangor Daily News — BDN Maine

Bud

 

I fly RC airplanes and some are powered by LiPo batteries and it has given me a great respect for lithium batteries. I've seen about a half dozen lithium battery fires and they are not to be trifled with. Luckily most in the hobby are aware of the danger and have special fireproof charging chambers to contain the fire and prevent further damage. Oddly though all my laptop, cell phone, Fitbit and other lithium powered devices don't get anything.

 

My Makita drills use the Li-ion batteries and unknown what else, but I plug them in and walk away as most people do. I imagine the list of appliances is long. Even though a fire may be statistically rare I will be finding a safe place for my charging process. I'm planning on this being my last home.

Thanks,
Bud

 

Being unfamiliar with the various lithium battery configurations and their extreme cost is why I chose lead-acid batteries for my lawn tractor. The L-A have only a fraction of the power along with a high weight disadvantage but the technology is over 100 years old with a proven track record.

And speaking of batteries, I think the SLA (gel-cells) in my push mower have finally died. I wanted to get 20 years but from what I have read on these mowers my 17 years is some kind of record.