A monthlong investigation found no design defects on the all-electric taxi involved in a fatal accident that caught fire and claimed three lives on May 26.

The report by a 13-member investigation team said that 25 percent of the 96 battery units in the taxi - an E6 all-electric car made by Shenzhen-based automaker BYD - burned in the accident but didn't explode.

"The car's battery system was appropriate in terms of installation and layout, insulation and the design of the high-voltage electricity system," Wu Zhixin, head of the investigation team, told reporters on Friday.