1) I don’t think Tesla’s battery day is about CATL, LG or Panasonic or even just Maxwell tech, it will be the reveal of Tesla’s in-house “Roadrunner” cell - likely the culmination of a 10 year+ project to solve cell capacity & cost with a bottom up redesign of Li-ion cell tech.
2) In my view Tesla’s cell design was largely complete when CTO & co-founder JB Straubel announced he was stepping down in July 2019, likely after thinking “My work here is done”.
3) Maxwell’s dry electrode tech is a key piece of the puzzle and Tesla has been testing their tech since at least 2016, however this IP only covers part of a very long and complicated cell production process:
4) Tesla is likely bringing in a lot more fully in-house R&D (including tabless cell design), research from its Jeff Dahn partnership (e.g. single crystal cathodes & careful electrolyte selection), experience from Panasonic at GF1 & other IP from M&A (e.g. Grohmann, Hibar)
5) Tesla is applying Elon’s trademark physics first principles engineering philosophy to cell design, but importantly the optimisation process has kept focussed on manufacturability...
6)... – so while it is a bottom up redesign of li-ion cells, it is mostly using techniques (& tweaks) which have already proven mass manufacturability (including Maxwell’s dry electrode method which is already used at scale for manufacturing ultracapacitors).
7) I don’t think Tesla will just be revealing an R&D cell on Battery Day. We know from environmental docs that Tesla has been been building a large scale cell manufacturing facility at Kato road in Fremont.
8) I think Tesla is likely to reveal mass production has already started and there is a reasonable chance they open orders for Plaid Model S which is likely to contain the first Roadrunner cells.
What format of cells will Tesla announce?
9) Short answer with very large error bars despite the specific predictions:
I think Tesla will announce its Kato road facility in Fremont has started production of 40mm-70mm cells with +25% volumetric energy density and 3.6x volume vs 21-70 cells, at 80-85Wh per cell.
10) At pack level I expect 30% volumetric energy density improvement using a cell to pack design (no modules). So a ~130KWh pack could fit into the same volume as the current ~100KWh Model S packs.
11) The energy density improvement is likely to be mostly from thicker cathodes (higher active material % of cell material – cathode is the bottleneck to cell energy density) enabled principally by Maxwell’s dry electrode tech. https://iopscience.iop.org/article/10.1149/MA2019-01/2/317
12) Tesla’s tabless cell design should significantly reduce resistance & enable a far larger new cylindrical cell format (high nickel cylindrical cell size is constrained by cell stability) reducing casing kg/KWh & increasing production rate (in KWh) https://twitter.com/enn_nafnlaus/status/1258801812288737285?s=20
13) At pack level I expect the extra volumetric energy density improvement (vs at cell level) to come from removal of modules, less cell separator and likely the integration of the top of the pack into the car body.
14) I expect Kato road will install a single "Roadrunner" cell line targeting 400k cells per day (= GF1 Panasonic cells/ line/day) or ~12GWh per year (vs 2.7GWh per cell line at GF1). Comfortably deliverable with the 38 trucks per day Tesla disclosed in its environmental docs.
15) Kato road will likely benefit from ~4-5x reduced footprint (in square metres) and labour hours per GWh capacity, much lower capex vs GF1 cells and pack costs significantly below $100/kwh.
16) Reaching target production level and cost is likely to take a long time and will take make upgrades of the production line design to overcome bottlenecks.
17) Tesla will apply agile development to its in-house cell manufacturing as it does everything else - so flexibility for rapid upgrades and iterations of the process to accelerate cost experience curves.
18) I expect almost full vertical integration at the facility starting from cathode powder mixing.
Tesla has disclosed it expects 170 manufacturing staff working at any given time, with 3 shifts in total.
Across the two Kato road buildings total footprint is 21,204 sqm.
19) What will the cells be used for and what about Panasonic/LG/CATL?
I think Tesla will likely use the first Roadrunner cells for Plaid Model S in Q4. It might aim for Kato road cells to eventually go into all S/X & Roadrunner cars (S/X packs are already made at Fremont).
20) Panasonic’s 8GWh 18-650 Japan factory could be converted into 21-70 format and exported to GF1 to support the Model Y ramp.
Tesla may import LG cells to GF1 for energy products and Semi and convert all 13 Panasonic lines to 21-70 cells for 3/Y (2 lines are normally energy).
21) In China I expect Tesla will use short term deals from CATL to produce SR+ Model 3 and Model Y, and LG for LR 3 and Y. Tesla may end its CATL contract once it has built Roadrunner lines in GF3.
22) I expect GF4 and GF5 to be fully supplied by Roadrunner cells from the start, but with backup plans to buy additional cells from CATL/LG or Panasonic if Tesla hit production ramp bottlenecks.
23) I expect Tesla to announce a roadmap to reach 2TWh of annual in-house battery cell+module+pack production capacity by 2030. Enough for ~20 million annual EV sales and ~750GWH annual stationary battery storage sales.
24) Longer thread on why Battery Day is one of several key milestones for the remainder of the year that suggests 2020 could be nearing endgame in Tesla's quest to drive an inevitable global Clean Energy transition. https://twitter.com/ReflexFunds/status/1293136443808845827?s=20
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