Date: 201711
Local time of day: 0601-1200
Location: ZZZZ.Airport, FO
Flight conditions: VMC
Light: Dawn
Aircraft: B787 Dreamliner Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
ATC / advisory: Center ZZZZ
Aircraft component: DC Battery
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Workload
Second reporter function: First Officer; Pilot Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew
When detected: In-flight
Result: Aircraft Equipment Problem Dissipated; Flight Crew Overcame Equipment Problem
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: On descent below FL180 on arrival; I first noticed a strong odor of food cooking (like garlic) and commented about it to the rest of the cockpit crew. The Flight Attendants later commented they had not been cooking anything; and I can only assume the odor may have been related to the battery. This smell went away after a few minutes. Although I am not certain of the sequence of messages that followed due to our workload at the time; I recall seeing two automatically generated FRM (Fault Reporting Manual) messages that were copied to our printer. I believe the first message made reference to a battery overheat and the second message referenced the battery charge being below a level adequate for dispatch. As the descent continued; I seem to recall the MAIN BATT LOW EICAS message appearing. There was no open square icon to the left of the message and therefore no electronic checklist to accomplish. The message subsequently disappeared from EICAS and; as I recall; was followed a few thousand feet later by the ELEC STBY SYS message that also eventually disappeared. Again; there was no square icon; and I asked the IRO to review the checklist in the FM. He did and advised both messages were advisory only. I also accessed the electronic checklist on the inboard display to make sure there was no unfinished checklist in the queue and found none.Although unrelated to the battery; I found it odd; as I did with a STABILIZER EICAS message on a previous flight several weeks ago; that these checklists show the square icon associated with them in the FM; but yet there is no square icon with the EICAS message displayed in the cockpit. My understanding is that the square icon indicates there are steps to be taken in the electronic checklists. In the case of these three checklists; there were none within the electronic checklist system in spite of the square icon in the associated FM checklist. I will conduct some review to make sure my understanding is correct.Given our proximity to the airport; our workload; and the lack of guidance from the checklists; we continued our approach without further regard to the battery and assumed the problem was either spurious or of little significance to us at that phase of flight. The approach; landing and taxi to the gate were uneventful. Upon arrival at the gate; I contacted [maintenance] by telephone to follow-up on the automatically generated FRM messages; and he indicated he had just seen them. A mechanic arrived at the aircraft shortly thereafter; at which point the IRO provided him with a comprehensive debrief.


Second narrative: [Report narrative contained no additional information.]


Synopsis: B787 flight crew reported that during descent they received a 'MAIN BATT LOW' EICAS message that eventually disappeared.