The 777 incident I mentioned was caused by a baggage handler dropping a suitcase that had a laptop in it. I read the incident report while I was on freq on our briefing system so the finer details escape me but I remember the cause and the airline involved. If li-ion batteries are mishandled then they can fail very easily, and the symptoms may not be noticed for quite some time. Luckily this 777 was on climb out when the crew got a fire warning, imagine if they had been at cruising level.....