Following Dell's massive battery recall last week, mobile device designers are beginning to worry that the problem may be larger than the 4.1 million recalled batteries used in Dell laptops. It also appears Dell's recall is not a cure-all.
"It's a matter of how systems are architected," Bodo Arlt, publisher of Bodo's Power Systems magazine in Germany told the EE Times, an online technology publication.
"You need to know how much energy the computer extracts from the battery, and how a system is designed to manage the current flow that generates heat inside the battery. Knowing the limitation at the critical temperature is important," he said.
In the wake of the recall, Sony, which manufactured the lithium-ion batteries, has taken much of the blame for the 12 reported incidents of burning laptops and hundreds unreported.
Reports suggest that faulty crimping on a Sony production line may have introduced metal contamination to the cathodes of the affected battery packs.
As was suggested in a ConsumerAffairs.com story on August 3, that contamination would likely yield some sort of combustion if the battery got too hot.
The Dell recall may not end stories of Dell laptops going up in flames. Thomas Forqueran, whose Inspiron 1300 set his truck ablaze, did not have one of the 4.1 million recalled batteries. The 1300 is not one of the listed laptops.
Some laptop designers believe that the architecture of the computer is to blame, not the rare battery defect.
Dell laptops frequently place the battery toward the front of the laptop - near the two hottest components of the computer - the CPU and graphics processor. Whereas Apple and Sony, which use the same Sony batteries Dell recalled, tend to place their batteries toward the back, which may explain why there is only one known case of an Apple laptop igniting and no Sony cases.
"If Dell used a thermometer that would automatically shut down the computer when the battery gets too hot, this could be avoided," Ronald Riley, president of the Professional Inventors Alliance USA, told ConsumerAffairs.com on August 3. "The point is, the computer should not be able to get hot enough to do that."
There are also concerns that with the increased demand for lithium-ion batteries, there may be more frequent quality control issues.
"It is basically a quality [control] problem in the cells," John Drengenberg, an electrical engineer and manager of consumer affairs for Underwriter Laboratories Inc. in Northbrook, Ill. told the EE Times. "Power density is increasing dramatically while battery cell materials have failed to keep pace."
If materials cannot meet the electrical and safety requirements, the task of keeping the battery cool may rest in hands of computer designers, not battery manufacturers.
A Sony spokesman in Tokyo said, "Our analysis thus far shows that a tiny metal particle that contaminated the electrolyte inside the battery cell caused a short-circuit." But he added, "Usually, that alone would not cause a fire, because the battery just goes dead at that point."
"We believe the fire was caused by the combination of batteries and system architecture," he said.
Dell has not commented on whether their architecture is to blame.