Tesla intends to begin mass production of long-life batteries within 3-4 years

Elon Musk suggested that Tesla would be able to mass produce batteries with an extended battery life and energy density of 400 Wh/kg within 3-4 years, which is the key to achieving a greater power reserve. The Panasonic "2170" battery currently in use in Tesla Model 3 has an energy density of about 260 Wh/kg.