SEOUL -- Tesla Inc. CEO Elon Musk has suggested the U.S. electric carmaker may be able to mass produce batteries with 50 percent more energy density in three to four years, which could even enable electric airplanes.
His comments came as speculation is growing about announcements at Tesla's anticipated "Battery Day" event where it is expected to reveal how it has improved its battery performance.
"400 Wh/kg *with* high cycle life, produced in volume (not just a lab) is not far. Probably 3 to 4 years," Musk tweeted on Monday in response to a Twitter thread by Sam Korus, an analyst at ARK Investment Management LLC, about why Musk keeps hinting at a Tesla electric plane.
Researchers have said the energy density of Panasonic's 2170 batteries used in Tesla's Model 3 is around 260 watt-hour per kilogram, meaning a 50 percent jump from the current energy density which is key to achieving a longer driving range.
Musk said last year that for electric flight to work, the energy density of batteries needed to improve to over 400 Wh/kg, a threshold which may be achieved in five years.
Tesla said Battery Day will take place on the same day as its 2020 annual meeting of shareholders on Sept. 22.
The automaker also showed a background image where a number of dots are clustered in line formations, sparking speculation among media and fans about what it will reveal at the event.
South Korean battery expert Park Chul-wan said the image may hint at "silicon nanowire anode," a breakthrough technology which can potentially increase both battery energy density and battery life sharply.
Panasonic earlier told Reuters that it plans to boost the energy density of the original 2170 battery cells it supplies to Tesla by 20 percent in five years.
Tesla is also working with China's Contemporary Amperex Technology Ltd. (CATL) to introduce a new low-cost, long-life battery in its Model 3 sedan in China later this year or early next year, with the batteries designed to last for a million miles of use, Reuters reported in May.
A very "limited number of stockholders" will be able to attend the Sept. 22 events due to pandemic-related restrictions, Tesla said, and a lottery will be held to select attendees.