All Nippon Airways (ANA) and Japan Airlines (JAL) have grounded their Boeing 787 fleets after an ANA aircraft made an emergency landing on Jan. 16 due to a suspected battery problem.

The incident, which comes hard on the heels of a battery fire in a JAL 787 on the ground at Boston Logan International Airport on Jan. 7, occurred during an ANA flight from Tokyo’s Haneda airport to Yamaguchi in western Japan. The aircraft, carrying 129 passengers and eight crew, diverted to Takamatsu.

Aircraft indicators showed “messages related to the battery” during the flight, ANA says. There was also “an unusual smell” in the cockpit and cabin. “Later it was confirmed that the main battery in the forward electronic equipment bay was discolored and the electrolysis solution had leaked,” says ANA.

Boeing says it is “working with our customer” but is not offering additional comment at this time. The aircraft is registered JA804A, and entered commercial service on Jan. 24, 2012.

ANA’s fleet of 17 787s has been grounded for inspections, in cooperation with the Japan Transport Safety Board. All of ANA’s remaining 787 flights on Jan. 16 were canceled, as were those scheduled for Jan. 17. There were 31 domestic and seven international flights canceled on Jan. 16. All 35 domestic 787 flights on Jan. 17 have been canceled, although the international 787 flights will be operated with different aircraft.

Meanwhile, JAL also suspended its 787 flights on Jan. 16 and Jan. 17, and says operations on Jan. 18 will be “decided after further assessment of the situation with the investigation.” On Jan. 16, JAL canceled five return international services that were scheduled to use 787s, and for a 787 flight from Narita to Singapore it used a 777 instead.

Japanese investigators and representatives of the Japan-based battery manufacturer GS Yuasa have joined the NTSB-led investigation into last week’s battery fire at Boston. The lithium-ion batteries, of which the 787 has two, are part of the Thales-supplied electrical power conversion system, and are the focus for the investigation.

(Updated with All Nippon Airways and Japan Airlines details)