It was a prototype of the battery charging system...
http://seattletimes.com/html/businesstechnology/2020199686_787batterysafetyxml.html
Same type of charger and same type of battery.
From your link, chargers not on the 787:
“and none are installed in Boeing 787 aircraft”
From here, not the same battery, chargers not on the 787:
“Boeing spokesman Marc Birtel said the 2006 fire resulted from “an improper test set up, not the design of the battery.” FAA spokeswoman Laura Brown said the agency “investigated Mr. Leon’s complaints in 2008 and 2009. The investigation determined that the battery charging units in the complaints were prototypes, and none are installed in Boeing 787 aircraft. “
“Boeing’s Birtel said the batteries referenced in the correspondence between Securaplane and the Pipeline and Hazardous Materials Safety Administration are not “the specific battery type currently under NTSB investigation or subject of the FAA emergency airworthiness directive.””