Driven

TESLA BAT­TERY DAY

TERA-FORM­ING THE AU­TO­MO­TIVE AND EN­ERGY IN­DUS­TRIES

- Re­port by WIL­HELM LOOTS | Im­ages © TESLA Business · Powerbanks · Clean Tech · Ecology · Consumer Goods · Gadgets · Tech · Nikola Tesla · Tesla Motors · Tesla Model S · Tesla Model 3 · Elon Musk · China · Tesla Roadster · Tesla Model X · Tesla

to sus­tain­able en­ergy. In 2019 the world pro­duced just 0.006 TWh of sta­tion­ary bat­tery stor­age, which im­plies a 1,600 fold growth re­quired in or­der to reach 10 TWh.

In to­tal the world would need 20 TWh of bat­ter­ies an­nu­ally, which is equal to the out­put of roughly 570 times the bat­ter­ies that Tesla will pro­duce this year.

THE PLAN

Tesla plans to pro­duce 100 GWh (gi­gawatt-hour) of bat­ter­ies in 2022 and 3 TWh by 2030. In or­der to re­alise this plan, Tesla de­vel­oped a roadmap to re­duce bat­tery costs by 56% on a $/kWh ba­sis, while in­creas­ing range by 54%.

To sim­plify the mag­ni­tude

an­nounce­ments, not to men­tion its lofty am­bi­tions, the in­no­va­tions that would en­able the bat­tery cost de­clines and ef­fi­ciency im­prove­ments are bro­ken down into seven cat­e­gories, each one as ground­break­ing as the next:

Cell De­sign – 14% re­duc­tion in $/KWh cost

Tesla’s new 4680 bat­tery cell is ar­guably the big­gest break­through in lithium-ion bat­tery tech­nol­ogy since its in­ven­tion nearly 50 years ago. The num­ber 4680 rep­re­sents a com­bi­na­tion of the di­am­e­ter (46 mm) and length (80 mm) of the new bat­tery cell.

Tesla started out with a much smaller 1865 cell form fac­tor, which is still used in the Model S/X, be­fore in­tro­duc­ing the 2170 cell form fac­tor for the Model 3/Y. The big­ger form fac­tor of the 2170 cell achieved a 50% in­crease in en­ergy com­pared to the 1865 form fac­tor.

The new 4680 bat­tery cell is a tab-less, dry-coated cell that adds five times more en­ergy, 16% more range, and six times more power. This trans­lates to a 14% re­duc­tion in $/kWh cost at the bat­tery pack level. Elon Musk was not ex­ag­ger­at­ing when he de­scribed the new 4680 cell as “a huge deal”.

Tesla is now in the process of ramp­ing up pro­duc­tion of the new 4680 cell to 10 GWh per an­num in its Kato Road pilot pro­duc­tion fa­cil­ity in Fre­mont. When at full pro­duc­tion ca­pac­ity, this “pilot plant” will be the 13th largest bat­tery fac­tory in the world. Cur­rently, Tesla’s Gi­gafac­tory Ne­vada – at 35 GWh of an­nual pro­duc­tion ca­pac­ity – is the largest bat­tery fac­tory in the world. Musk also re­vealed that the new 4680 cells have been used in cars since May this year.

Fac­tory De­sign – 18% re­duc­tion in $/KWh cost

Tesla’s new dry coated elec­trode process in­creases speed and re­duces foot­print. New cell assem­bly lines are de­signed to op­ti­mise con­tin­u­ous move­ment with a seven times im­prove­ment in line out­put. Ef­fi­cien­cies gained from for­ma­tion op­ti­mi­sa­tion – the process of form­ing, charg­ing and test­ing each cell – now en­able Tesla to achieve a fur­ther 86% re­duc­tion in for­ma­tion in­vest­ment and 75% re­duc­tion in for­ma­tion foot­print. Com­bined with its new dry coated elec­trode man­u­fac­tur­ing process, this leads to a 75% re­duc­tion in in­vest­ment per GWh and a 10 times re­duc­tion in foot­print per GWh, which is at least four times bet­ter than any ex­ist­ing bat­tery man­u­fac­tur­ing plant to­day, in­clud­ing Tesla’s Gi­gafac­tory Ne­vada. This trans­lates to Tesla achiev­ing 1 TWh of cell pro­duc­tion in a fac­tory that is smaller than the 150 GWh Gi­gafac­tory Ne­vada. All of these man­u­fac­tur­ing im­prove­ments trans­late to an 18% re­duc­tion in $/KWh cost at the bat­tery pack level.

An­ode Ma­te­ri­als – 5% re­duc­tion in $/KWh cost

Musk and Baglino re­vealed a revo­lu­tion­ary new use of sil­i­con in the bat­tery an­ode as one of the ma­jor steps to­wards re­duc­ing cost and in­creas­ing ef­fi­ciency. While sil­i­con can store nine times more lithium than graphite, sil­i­con also ex­pands four times its vol­ume dur­ing charge/dis­charge cy­cles, which causes the sil­i­con to de­form, and be­come un­sta­ble over time. By sta­bil­is­ing the raw met­al­lur­gi­cal sil­i­con with Tesla’s pro­pri­etary elas­tic, ion-con­duct­ing poly­mer coat­ing, and then in­te­grat­ing the sil­i­con with the elec­trode us­ing Tesla’s pro­pri­etary highly elas­tic binder, Tesla has man­aged to con­tain the ex­pan­sion stress on the sil­i­con par­ti­cles dur­ing charge-dis­charge cy­cles. The use of raw met­al­lur­gi­cal sil­i­con, along with Tesla’s se­cret in­gre­di­ent, will de­crease $/KWh cost by 5% at the bat­tery pack level, while in­creas­ing range by up to 20%.

Cath­ode Ma­te­ri­als – 15% re­duc­tion in $/KWh cost

Cur­rently, bat­tery cell cath­odes con­sist of any one or a com­bi­na­tion of me­tals, mainly iron, man­ganese, cobalt, alu­minium and nickel, which sep­a­rately, or in com­bi­na­tion, pro­vides the nec­es­sary sta­bil­ity to store lithium ions dur­ing charge/dis­charge cy­cles. Tesla’s pre­ferred choice is nickel be­cause of its cheaper price and rel­a­tively high en­ergy den­sity and sta­bil­ity, and while cobalt of­fers even higher en­ergy den­sity and sta­bil­ity, its sus­tain­able pro­duc­tion is limited be­cause of eth­i­cal min­ing con­cerns and there­fore it re­mains sub­ject to price fluc­tu­a­tions.

Tesla’s new high nickel cath­ode has no cobalt in it, and in­stead uses Tesla’s pro­pri­etary coat­ings to pro­vide sta­bil­ity. This alone en­sures a 15% re­duc­tion in cath­ode $/KWh cost. How­ever, since nickel is more ex­pen­sive than some of the other cath­ode ma­te­ri­als, and not re­ally nec­es­sary in all ap­pli­ca­tions, Tesla is tak­ing a horses-for-courses ap­proach to its cath­ode solution across var­i­ous prod­ucts and mod­els. As such Tesla plans to use iron cath­odes with a long cy­cle life (read mil­lion mile bat­tery) in the Model 3 Stan­dard Range, a new smaller $25,000 model man­u­fac­tured as two sep­a­rate mod­els in Europe and China re­spec­tively, as well as its grid stor­age Pow­er­packs. For long range ap­pli­ca­tions – Model S/3/X/Y and res­i­den­tial Pow­er­wall – Tesla will use a nickel/man­ganese cath­ode. Fi­nally, a high nickel cath­ode will be used in high mass, long range ap­pli­ca­tions like the Semi and Cy­ber­tuck, and more than likely in the new Plaid bat­tery and pow­er­train des­tined for the Tesla Road­ster, Model S and Model X.

More than that, and in typ­i­cal Elon Musk style of ap­ply­ing “first prin­ci­ples think­ing” to ev­ery en­gi­neer­ing prob­lem, Tesla has sim­pli­fied the ex­trac­tion of nickel from nickel ore to achieve a 66% re­duc­tion in capex in­vest­ment and a 76% re­duc­tion in process cost, with zero waste wa­ter.

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