I have found information that Tesla's 70 kWh battery pack has 63 kg of lithium: https://electrek.co/2016/11/01/breakdown-raw-materials-tesla-batteries-possible-bottleneck/
Considering there's only 13 million tonnes of lithium reserves, this would mean only 200 million of these Tesla's battery packs could be manufactured, unless new lithium reserves are discovered. Big problem.
However, Wikipedia says that lithium provides 11.6 kWh per kg: https://en.wikipedia.org/wiki/Lithium-ion_battery ...which would mean that Tesla's 70 kWh pack requires only 6 kg of lithium, meaning 2.2 billion such battery packs could be manufactured, which is probably enough for the world's needs (not every car requires a 70 kWh battery). Also, if this information is true that 11.6 kWh of energy can be stored per kg of lithium, major grid energy storage could become a reality.
Also, this stack exchange answer: https://electronics.stackexchange.com/questions/34501/how-much-lithium-in-lithium-polymer-batteries ...says 8 g / 100 Wh of lithium is needed, meaning 12.5 kWh per kg, which is about the same as Wikipedia's information.
Is the Tesla battery really such an inefficient user of lithium, or is the information that it has 63 kg of lithium incorrect? If the Tesla battery is an inefficient user of lithium, why is that the case?