By Deepa Seetharaman
DETROIT (Reuters) - Underwriters Laboratories, a 119-year-old U.S. company that develops product safety tests, is strengthening its lithium-ion battery standards after a string of high-profile battery failures that shed light on the technology's weak spots.
Those vulnerabilities were highlighted this year when regulators grounded Boeing Co.'s 787 Dreamliner for nearly four months after lithium-ion batteries overheated on two separate jets in January, leading to a fire in one.
Even so, analysts expect a growing number of products to rely on the batteries, which are more powerful and resilient than their traditional counterparts. The global market for lithium-ion batteries is expected to double by 2016.
In articles published on its website on Wednesday, Underwriters Laboratories said it has developed a more vigorous test to prevent short circuits inside the battery cell that can lead to a fire. It is also refining safety and testing standards for larger batteries increasingly used in hybrid and electric cars.
"The number of lithium-ion batteries in use, the complexity of the lithium-ion battery cells and the numerous usage conditions make the design of safe cells and the development of tests for battery safety standards extremely challenging," Underwriters Laboratories said.
The use of the batteries has greatly expanded in the past decade, powering everything from the Chevrolet Volt to iPads. The number of lithium-ion cells made worldwide ballooned to 4.4 billion in 2012, from 800 million in 2002, according to the Portable Rechargeable Battery Association, a trade group of battery makers.
Still, Boeing's crisis illustrated how battery experts are trying to understand the risks posed by large-format batteries, as well as what causes internal short circuits implicated in the Dreamliner problems.
GS Yuasa Corp. (6674.T) of Japan makes the 787 battery and Thales SA (TCFP.PA) of France makes the battery system.
The U.S. Consumer Product Safety Commission has documented more than 350 fires involving lithium-ion batteries since March 2012, Underwriters Laboratories said.
Underwriters Laboratories worked with officials at NASA and Oak Ridge National Laboratories to develop its internal short test. This method is now part of NASA's battery qualification process for space flights.
(Reporting by Deepa Seetharaman; Editing by Dan Grebler)