Some thoughts on lithium demand in the household/grid storage space?This is a big unknown because the energy density strength of lithium-ion batteries is not as relevant. If making a battery for household appliances, computers, cell phones or even EV's you don't want the battery to be excessively heavy therefore you want higher energy density.
If being attached to the side of a house, people often want a less bulky unit but still want the energy capacity so energy density still matters. In an apartment situation smaller size may be essential. Li-ion batteries step in again. The difficulty for Li-ion batteries is that despite being packaged as bigger bundles, they are inherently something like multiple AA to D sized batteries or a combination of cellphone battery pouches. There may be limits to how many of these units can effectively be combined. EV makers have scaled to 30-100kWh batteries by using thousands of these individually small batteries. The new Tesla 4680 battery is larger at 46cm wide and 80mm long (as context a "D" size battery is 33mm wide and 61.5mm long).
From Google:
So back to grid storage - where not that many kWh's are needed Li-ion batteries may be an effective solution.
Many grid systems will need capacities measured in mWh not kWh and this may need to be GWh if multi-week or seasonal load transfer is required. With mWh being 1,000x a kWh, and a GWh being 1,000x a mWh, the capacity increases beyond whats needed for an EV are huge. Being small with a high energy density is no longer key. Within this grid (not household) space, Vanadium based redox flow batteries are an option being commercialised. The article below notes a 40mWh battery has been built in Hubai China and a 100mWh battery is being commissioned. This battery style is only suited to stationary applications so is not a threat to lithium demand for EV's. It conceptually is two tanks of liquids and other materials that are kept separated by a thin membrane. When charging one tanks builds up positive charges, the other negative charges. When providing power the process is reversed. This can theoretically be repeated for 20+ years.
Because power companies/government can build big, it doesn't matter that redox flow batteries may only have an energy density around 10-20Wh/kg. As context, car lead-acid batteries are 25-35Wh/kg. Newer Li-ion designs are up to 265Wh/kg. If these other systems were used in Tesla powerwalls the unit size would need to be around 10x as large for the same capacity the size. I think Li-ion solutions will continue to exist at the consumer end of the grid market. If power prices start increasing, then even more powerwalls and similar will be installed (additional lithium demand). If done with Li-ion batteries, a grid 82mWh system would appear to require around 806,000 batteries of the 4680 type. If smaller individual battery types like 2170 are more cost effective, it could require several million individual batteries. While possible, I don't think this is the most likely solution for grid scale storage.
Some useful background on vanadium redox flow batteries is included below.
https://www.sphere-energy.eu/sphere-blog/china-continues-to-lead-the-way-on-grid-energy-storage-with-commissioning-of-new-100mw-flow-battery-system
Disc - no current holding in vanadium but its something I'll consider over the next few years
