The latest consumer device to burst into flame made us wonder: Are manufacturers doing anything to guarantee the safety of their lithium-ion batteries through better quality assurance (QA) testing? The surprising answer: Not really.
Gadget Lab called Marijana Vukicevic, a senior analyst of
power management at iSuppli, to find out about the current state of battery manufacturing. What she had to say about the testing methods employed by various consumer electronics manufacturers gave us pause. Turns out, even after the massive battery recalls of 2006 and 2007, most companies still use what seem like incredibly low standards for battery quality testing.
"Usually when they test these devices, they test only one batch that comes off the manufacturing line," Vukicevic said. "They'll perhaps sample 25 out of thousands in a given batch. Even if one or two fails out of that 25, they will assume those devices are OK," she added.
What? Two failures out of 25 is a pass for the entire batch of thousands of batteries? Granted, these are rigorous tests that measure battery performance in a number of different extreme heat and moisture conditions. The tests often take days to complete. Still, if 2 out of 25 of your devices are failing a battery test, that seems like an awful big gamble for companies to take. Sony, you may recall, spent $429 million on its own battery recall in 2006.
According to iSuppli, manufacturers use such low criteria because quality testing is considered way too expensive to employ across broad swaths of newborn devices. What's more, there's always an expectation of some rate of failure, since there are always a number of unknown factors (not necessarily battery related) that can cause problems, said Vukicevic. Faulty circuitry, using a higher current than the battery spec, or a variety of different environmental conditions can set off an unpleasant chain of events ... as we've seen before.
Still, you'd think the 10 million recalled batteries might prompt the industry to be a bit more thorough in its testing. Apparently not.
We also took the opportunity to ask Vukicevic about one comment on our previous post regarding the presumed danger of extended charging times.
"Leave your car charging for 12 days and blame the maker if it explodes. Sorry. Charging it for an extended period is the owner's fault," reader Ed said.
Sorry, Ed, that's not true when it comes to modern electronics. Vukicevic said that today every device has circuits built into them that recognize when the battery is fully charged. Once this happens, circuitry within the battery shuts off the current, she said. That's not to say these circuits don't occasionally malfunction, but in almost all cases, Vukicevic says it's absolutely safe to leave your phone, laptop or any other device plugged in for as long as you want.
Battery University, an online resource for general battery knowledge, notes that all lithium-ion batteries have these protection circuits to maintain safe operation:
