On Thursday the U.S. agency that investigates air crashes called for lithium-ion batteries on Boeing's 787 Dreamliner jets to undergo more testing to ensure they are safe. The 250-seat jetliner, which has a list price of around $212 million, has been plagued with problems since it was introduced in 2011.

The National Transportation Safety Board (NTSB) urged the Federal Aviation Administration (FAA) to develop better tests to evaluate and certify the batteries, which have in some cases overheated and led to battery fires.

The NTSB is also recommending that the FAA require the tests for future aircraft designs and check whether 787s and other planes that have similar batteries need more testing. The agency, which stopped short of calling lithium-ion batteries or planes flying with them unsafe, can only make recommendations — it would be up to the FAA to decide whether to act.

Lithium-ion batteries are widely used in cars, laptops and smartphones and have a tendency to overheat through processes that are not well understood by scientists.

The NTSB criticized the FAA, Boeing and battery-maker GS Yuasa Corp of Japan. Recent NTSB tests showed results are affected by environmental factors, such as how the battery was installed and the temperature of the air around it. The testing protocols for the battery, however, were "inadequate" because they didn't properly account for real world conditions.

"There is no standardized thermal runaway test that's conducted in the environment and conditions that would most accurately reflect how the battery would perform when installed and operated on an in-service airplane," the NTSB said on its website.