June 29, 2022

Tesla’s 4680 cell production process outlined in revised Giga Berlin documents

Tesla’s revised documents for Gigafactory Berlin have been posted online and are a wealth of information. The documents provided new details about Tesla’s planned 4680 battery factory at Gigafactory Berlin, which Elon Musk says is set to become one of the largest battery production facilities in the world. They also explained how Tesla’s 4680 cells are produced.

While sections of the filing relating to the planned 4680 battery cell plant at Giga Berlin have been blacked out due to sensitive information that could not be made public, the documents show some important information about the facility at to come. This includes the facility’s cell production operations on four floors, with anode and cathode production on the first floor and tableless cell production on the third floor. The Battery Factory is massive and requires large foundations similar to the Phase 1 area of ​​Gigafactory Berlin.

More importantly, Tesla also submitted a simplified schematic of its 4680 battery cell production process, although most of the schematic was hidden in the public version of the revised filing. However, the company has provided a brief overview of how its new battery cell will be produced in the next facility (about translated via Google Translate).

“The battery at Gigafactory Berlin requires special systems and process steps. The anodes and cathodes consist of coated current collector foils. Copper is used as the material for the anode foil and aluminum is used for the cathode foil. The anode and cathode components are manufactured in mixed processes (A020-01 and A020-02) which only use materials in powder form. The new materials used are tested and approved in our own laboratory (A020-11).

“For the powder coating to adhere to both films, they must first be pre-coated with a thin layer of adhesive (substrate) (A020-03 and A020-04). This substrate is delivered in containers. Pre-coating is necessary because a dry coating with powder takes place. After the anode and cathode components are mixed, they are applied as a coating to the coated film of the respective substrate to establish electrical contact (A020-05 and A020-06). The current collector foils, coated with the anode or cathode components, yield the finished anode or cathode.

The reviewed documents also provided a general idea of ​​how Tesla’s tableless cell production works. Among these is the fact that the finished 4680 cells would be subjected to 10 days of curing after their formation.

“The anode or cathode is then cut to the required lengths with a laser in the “tabless process” (A020-08). The anode, cathode and separator are alternately laid on top of each other and wound into a roll. This roll is then inserted into a metal casing, which is fabricated from steel rolls in a cutting and deep drawing process (A020-07).In the assembly area, final assembly and filling of the cell take place with small amounts of electrolyte (about 10% of the weight of the cell) (A020-09).

“The electrolyte is absorbed by the coatings of the electrodes and allows the lithium ions to come and go between the anode and the cathode. The case is then closed with a lid in a welding process. The last step is the formation (A020-10) of the cell. In the forming process, the cell is started electrically by charging and discharging it under different temperature conditions. The finished cell remains in this area for approx. 10 days and is then reused. The cells produced are subject to random quality control in our own laboratory (A020-11).

A link to Tesla’s repositories for Gigafactory Berlin could be found here.

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Tesla’s 4680 cell production process outlined in revised Giga Berlin documents