Pedantic comparisons between inexpensive mass produced batteries (over 2 billion mobile devices, laptops and tablets sold in 2012) and the 787 batteries is as foolish as equating the map application on your smartphone to the Honeywell navigation package on the 787.
The difference is that 'cheap' mass produced batteries and chargers are about a million times less likely to result in a battery fire than a 787 battery.
The 787 battery/electrically system has a statistically proven chance of failure every 25,000 hours. 3 years. That sort of reliability in consumer devices would see multiple daily phone/laptop fires in a office building of a 1000 people.
In the Uk there would be around 30million battery fires per year, every night would be like the Blitz, except with fires all around the country.
The acceptable level of risk is one in a billion flight hours, not one in 25,000