> Having worked extensively with battery systems, I think the grid storage potential of second-life EV batteries is more complex than it appears.
Complex, by t very much doable. Toyota implemented such a system with enough packs to power a Mazda factory [1]
> However, you need to factor in significant integration costs (~$50-75/kWh) to build compatible BMS systems and thermal management.
Shouldn't this be a once-off cost per battery-pack version? Or was this your armortized cost for your deployment capacity. If you've written the BMS for a 2019 Model 3 Panasonic battey pack once, won't you reuse it for all the subsequent battery packs of the same model/SKU?
> Shouldn't this be a once-off cost per battery-pack version?
A BMS isn't just software. It requires a µC, voltage and temperature sensors for cell monitoring, and power electronics for cell balancing. However, those are all comparatively cheap, especially at scale, and the quoted cost of 50–75 US$/kWh looks ridiculously overpriced to me.
I expect EV batteries to have all those components preinstalled already, and naively thought the grid-integration involves reverse engineering the battery's protocol, and perhaps bypassing/replacing a µC or 3.
Complex, by t very much doable. Toyota implemented such a system with enough packs to power a Mazda factory [1]
> However, you need to factor in significant integration costs (~$50-75/kWh) to build compatible BMS systems and thermal management.
Shouldn't this be a once-off cost per battery-pack version? Or was this your armortized cost for your deployment capacity. If you've written the BMS for a 2019 Model 3 Panasonic battey pack once, won't you reuse it for all the subsequent battery packs of the same model/SKU?
1. https://news.ycombinator.com/item?id=44998010