GRA
Well-known member
Via GCC:
With max. theoretical specific energy of Li-ion cells about 400 Wh/kg, and max. practical value unlikely to exceed 300-350 Wh/kg when fully developed, that would limit a Model S size/weight pack to a max. of about 115kWh, assuming that increases in energy density (Wh/l) are comparable to increases in specific energy. What that means is that comparable to ICE range at anything approaching ICE weights just isn't possible for Li-ion batteries, and it will require a change to Li-Si or more likely Li-S, Li-air or some currently even less well-developed tech to get to the range needed, especially if that range is to be provided for smaller cars as well as large ones.
Gasoline's specific energy is around 12,000Wh/kg (albeit it's used at much lower efficiency). Most estimates I've seen indicate that it will take cell specific energies of at least 800-1,000 Wh/kg and comparable energy density to provide compacts and smaller cars with ICE range at comparable weights. IIRR that's beyond the theoretical limit of Li-Si, which is likely the next major battery tech to be commercialized. Those wishing to delve more deeply into the reasonably current state of the art are directed to "Advances in Battery Technologies for Electric Vehicles"; 2015; ed. Scrosati, Bruno; Garche, Jurgen; and Tillmetz, Werner: http://store.elsevier.com/Advances-in-Battery-Technologies-for-Electric-Vehicles/isbn-9781782423980/
A good familiarity with chemical equations and chemistry in general or better yet electrochemistry is very helpful, as otherwise much of the book will be so much greek (as, having forgotten most of what little chem I took, it was to me). Fortunately, not all of the chapters are heavy sledding, and those chapters/sections that are excessively technical can be read by the 'blah blah blah' method. Many of the chapters on older battery types can be skipped completely.
http://www.greencarcongress.com/2016/06/20160629-ford.html
Note this is for all steps up to roll out from the factory "gate", not subsequent use. Of interest is this:
That's 80Wh/kg for the pack. Tesla's 85kWh pack is in the 140Wh/kg range IIRC, and the 90 would presumably be a bit higher. That compares to 260? Wh/kg for the cells in the S85 pack.
With max. theoretical specific energy of Li-ion cells about 400 Wh/kg, and max. practical value unlikely to exceed 300-350 Wh/kg when fully developed, that would limit a Model S size/weight pack to a max. of about 115kWh, assuming that increases in energy density (Wh/l) are comparable to increases in specific energy. What that means is that comparable to ICE range at anything approaching ICE weights just isn't possible for Li-ion batteries, and it will require a change to Li-Si or more likely Li-S, Li-air or some currently even less well-developed tech to get to the range needed, especially if that range is to be provided for smaller cars as well as large ones.
Gasoline's specific energy is around 12,000Wh/kg (albeit it's used at much lower efficiency). Most estimates I've seen indicate that it will take cell specific energies of at least 800-1,000 Wh/kg and comparable energy density to provide compacts and smaller cars with ICE range at comparable weights. IIRR that's beyond the theoretical limit of Li-Si, which is likely the next major battery tech to be commercialized. Those wishing to delve more deeply into the reasonably current state of the art are directed to "Advances in Battery Technologies for Electric Vehicles"; 2015; ed. Scrosati, Bruno; Garche, Jurgen; and Tillmetz, Werner: http://store.elsevier.com/Advances-in-Battery-Technologies-for-Electric-Vehicles/isbn-9781782423980/
A good familiarity with chemical equations and chemistry in general or better yet electrochemistry is very helpful, as otherwise much of the book will be so much greek (as, having forgotten most of what little chem I took, it was to me). Fortunately, not all of the chapters are heavy sledding, and those chapters/sections that are excessively technical can be read by the 'blah blah blah' method. Many of the chapters on older battery types can be skipped completely.
