I follow EOS for quite some time. They got two zinc-air technology, one regular rechargeable cells, and another flow battery.
The quote above is referring to flow battery design.
As for the topic, EOS should start commercial production of regular(non-flow) cells by the end of this year(at least this is the goal). Not sure where 5x times energy density number came from, but they got cells that have specific energy at around 500Wh/kg. Moreover, the cells EOS testing at the moment do not show any signs of degradation after few years of full charging/discharging daily. EOS itself think that their cells should last for 25 to 30 years.
Another huge selling point - $160 per kWh price. All materials used are cheap. And safety is superb.
Does those characteristics make EOS zinc air batteries a wonder batteries for EV applications? The answer is not really. Devil is in the details.
Just like with any other metal air chemistry power density is very low. Around C/6. So for Model S to sustain highway speed it should be equipped with north of 300kWh zinc air battery pack. EOS recognize that shortcoming and is talking about hybrid battery design. Zinc-air is for main supply of power and li-ion is for short term bursts of power(acceleration, regenerative breaking). And Tesla got at least one patent that describe such hybrid battery design, what really interesting that when Tesla counted metal air chemistries that could be applicable to the patent, zinc air was mentioned on the first place.
Second drawback - somewhat low charge/discharge efficiency. To fully charge 75kWh pack one would need to put 100kWh into it. To fully charge 100kWh pack - 133kWh should be spent.
And I totally clueless about self-discharge characteristics of zinc air in general and EOS cells in particular.
