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IT Home reported on November 4 that Munro Live has released a full, in-depth video analysis of Tesla's Cybercab, including a vehicle teardown and an on-site tour of the Cybercab production line at Tesla's Giga Texas factory. The tour was led by Tesla Vice President of Vehicle Engineering Lars Moravy, Cybercab program lead Eric Earley, and several team members involved in developing the purpose-built Robotaxi.
The visit covered every stage from the battery pack to final vehicle assembly. Here are some of the most noteworthy points.
The battery pack can finally be repaired separately
The biggest change is in the battery pack's design. Cybercab still uses Tesla's 4680 cells, but instead of packaging all the cells into a single integrated structure as in the Model Y, it divides them into multiple individually packaged modules. If one module fails, Tesla only needs to replace that module, rather than the entire battery pack.
The head of Tesla's battery department was candid about the earlier design. He said, “I give the Model Y's structural battery pack a D.” He considers it an excellent product for consumers, but difficult and expensive to manufacture. By comparison, he gave the Cybertruck's battery pack a B- and the Cybercab's an A-.
A fully structural battery pack can hold about 10% more cells, but given repair costs, that design is unsuitable for a commercial Robotaxi that needs to operate around the clock, 24 hours a day. As Earley put it, “If you have to replace the entire battery pack before the vehicle reaches 500,000 miles, that creates a huge cost burden.”
The Cybercab battery pack also has several other noteworthy improvements:
First use of a steel battery pack enclosure: This is the first time Tesla has used steel in a battery pack. Although steel is heavier, it costs about $1.9 per kilogram (IT Home note: about 12.7 yuan at current exchange rates), versus $5 to $8 for alternative materials (about 33.4 to 53.5 yuan at current exchange rates). Tesla therefore believes it remains more cost-effective overall.
More space around the modules: Extra space has been left around and beneath the battery pack modules. This is partly because Tesla found it needed fewer cells than expected, and partly to leave room for lower-cost lithium iron phosphate (LFP) cells in the future.
Wireless communication between battery management circuit boards: The battery management circuit boards communicate wirelessly with one another, eliminating the wiring harness.
Pyrotechnic fuses eliminated entirely: Tesla has applied for a patent for this new design. A new contactor can quickly cut power while under load. Tesla says many pyrotechnic fuse activations actually occur in “low-speed collisions where the high-voltage system itself has not been damaged.” Under the previous design, such cases could require replacement of the entire battery pack.
Battery electronics serviced from below: According to Tesla's data, the cells themselves are more reliable than the electronics around them, so the new design places the access point for servicing the electronics on the bottom of the battery pack.
New inverter may be used in the Model Y in the future
Cybercab is front-wheel drive and uses an all-new drive unit with an 11:1 gear ratio, higher than the roughly 9:1 ratio used in most Tesla models. Cybercab does not need a very high top speed, allowing it to use this gear ratio.
The new inverter has fewer parts than the current version, and every part can be supplied by at least two vendors, helping reduce supply chain risk.
Nick Verzani, Tesla's head of drive units, said production of the new inverter's circuit boards and power-stage components will begin at the Fremont factory this year, and that the complete inverter can be fitted directly into the Model Y's drive unit.
Asked whether this inverter would actually be used in the Model Y, Moravy replied, “I plead the Fifth.” This is a common way to avoid answering in a U.S. legal context.
Tesla also revealed that the same drive unit will be used in the Semi electric truck. Model 3 and Model Y may therefore soon receive related upgrades as well.
Tesla also plans to reduce gear transmission losses by 7% later this year by adopting a new lubricant. The drive unit uses a lower-cost mechanical oil pump, while the inverter can be serviced directly from above the vehicle, without lifting it or removing the entire drive unit.
Paint shop eliminated; target lifespan of at least 500,000 miles
Cybercab eliminates the traditional paint shop entirely.
Moravy said building a paint line requires an investment of hundreds of millions of dollars and about 1 million labor hours. Tesla no longer even applies electrophoretic coating to the front and rear body modules, because the aluminum alloy used in its castings does not lose strength over time as other aluminum materials do.
Only the side modules require coating. They use boron-steel door-ring structures to improve protection in a side impact.
Cybercab's body panels get their color directly through the Reaction Injection Molding (RIM) process. Tesla says scratches on the body can still be repaired in the same way as conventional automotive paint.
These designs are intended to extend the vehicle's service life. Moravy said Tesla has at least doubled the vehicle's designed service life, adding, “This car can go at least 500,000 miles.”
Unboxed manufacturing process: A major increase in production efficiency
Moravy said Tesla's past attempts at automated production ran into bottlenecks because “the problem wasn't automation itself, but the product design.”
The Unboxed manufacturing process used for Cybercab divides the vehicle into front, rear, side and central modules. These modules are manufactured and tested separately, then assembled at the end, making the process better suited to automated production.
The production process yields a series of striking figures:
Final assembly requires just 25 fully automated stations: By comparison, the Model Y production line has about 5 to 10 times as many stations.
The entire production line is about 78% automated: Tesla is currently working to raise that figure to 100%.
Factory floor space reduced by about 50%: The Unboxed manufacturing process can cut the production floor space required per vehicle by roughly half.
Front module assembled on a pallet: The front module contains about half of the vehicle's parts. During production, it is first placed on a pallet, then the body is lowered onto it from above for assembly.
First use of brake-by-wire technology: Cybercab is Tesla's first model to use brake-by-wire, allowing the front and rear braking systems to be tested separately.
Wheels installed near the end of the production line: The wheels are installed at the second-to-last station by a robot named Hulk Hogan. As a result, Cybercab does not actually touch the ground for the first time until it leaves the production line.
The production line is currently capable of producing vehicles faster than they are being deployed to the Robotaxi fleet, so it does not run every day.
Gullwing doors and other design details
Discussing Cybercab's gullwing doors, Tesla acknowledged, “The most fundamental reason is that they're cool.”
The design also has practical uses. Cybercab's seat height matches that of a standard wheelchair, and the upward-opening doors give passengers more room to move their feet out of the vehicle while also providing some shelter from rain.
The vehicle's thermal management system has also been redesigned. The new system moves most of the complexity to the coolant-loop side, keeps the refrigerant loop sealed, and mounts the air-conditioning compressor directly on the Supermanifold thermal management manifold.
This design makes servicing easier and also makes it easier for robots to take part in production assembly.
What comes next?
Tesla has already deployed more than 300 Cybercabs in Austin and expects to launch Robotaxi passenger service in Dallas this month. Tesla also plans to deliver the first Cybercabs to customers before the end of this year.
Cybercab production capacity is already ahead of the actual pace of Robotaxi fleet deployment, while production of the new inverter is also scheduled to begin at the Fremont factory this year. This means some of the engineering technologies and design approaches used in Cybercab may soon be applied to other Tesla models.