Tesla Structural Battery Pack, the good and the bad

By Henry Farkas

Back in September of last year, Tesla had its Battery Day presentation (full video below). In January of this year, Electrek wrote an article about the Tesla structural battery. So why am I writing about this now? The structural battery pack was just a gleam in Elon Musk’s eye at that time, but soon, there will be cars that incorporate the new design. Here’s what you should think about if you’re considering buying a Model S Plaid or a Cybertruck with the structural battery pack.

Tesla's structural battery

As Elon said during the presentation, the structural battery pack was inspired by the airline industry. They used to put gas tanks in the wings of airliners. The tanks added weight. More weight meant more fuel needed to fly. Eventually, the aircraft manufacturers figured out that they could save weight if the wings were the gas tanks. They saved weight that way. It’s the same with battery packs. Right now, there are battery cells that are put together in modules. The modules add weight. Then the modules are put together into a large battery pack. That adds more weight. Then all that stuff is put into the structure. More weight means less range.

Tesla engineers figured out that they could save lots of weight if they eliminated modules and if the battery pack was the structure. They do that by making a honeycomb structure with all the wiring and cooling coils inside it. Then they drop in the 4680 cells and epoxy them to the honeycomb structure. For those of you who are not aware, the designation, 4680 refers to the 46mm diameter of the battery cells and the 80mm height of the Tesla cells. Those battery cells are larger than the ones currently in use by all previously made Teslas so they store more power in each cell. For comparison, visualize the current Tesla battery cells being like AA batteries and the 4680 cells being like D batteries. Remember D batteries?

Plane's structural battery

The following picture is from the article in Electrek cited above. You can appreciate the honeycomb pattern of the pack, a structure known for strength and light weight. The coolant loops are built into the sides of the pack.

Tesla honeycomb battery shape

So saving weight, stronger cells, less of them. More battery, less other stuff. It’s all good, right? Maybe.

Here’s the bad part.

If the car gets in an accident and the battery pack is breached, you can’t just take out the old pack and drop in another pack. That might not matter because chances are pretty good that an accident bad enough to damage the battery pack will total the car. From an individual’s perspective, that’s why you get insurance. But there are other considerations if you care about the environment you’re leaving to my grandchildren.

Batteries should be recycled. So far, they’re not designed for recycling. With technology at its current state, it’s cheaper to mine new materials than it is to recycle the materials from used batteries. The ability to recycle gets worse when the batteries are epoxied into a big honeycomb structure. I’m not a chemical engineer so I can’t offer any suggestions about how battery cells could be designed to make recycling cheaper than mining new materials, but they should be designed that way.

The other bad thing about the structural battery pack is that cells don’t all deteriorate at the same rate. With the current battery packs, bad cells can be detected and switched out for good cells to rejuvenate the range of an old Tesla. That won’t be feasible with the structural battery pack. That may or may not be important. It depends on whether the cells last as long as the rest of the car or not. Time will tell, but it’s something to think about if you plan to keep your car for the million miles that Tesla claims their cars are designed to last.

Here is Tesla's 'Battery Day' presentation. If you care exclusively about the structural battery, you can jump to the 1 hour, 19 minute mark.

Henry Farkas is a retired country doctor. He bought his Tesla Model 3 in the middle of the pandemic.

Everything we know about Optimus, the Tesla Robot

By Kevin Armstrong
Optimus carrying a package using Tesla Vision
Optimus carrying a package using Tesla Vision
Tesla (Edited by Not a Tesla App)

Elon Musk started Tesla's AI Day 2022 by saying, "I want to set some expectations with respect to our Optimus Robot," just before the doors opened behind him. A robot walked out, waved at the audience, and did a little dance. Admittedly a humble beginning, he explained, "the Robot can actually do a lot more than what we just showed you. We just didn't want it to fall on its face." Musk's vision for the Tesla Robot, "Optimus is going to be incredible in five years, ten years mind-blowing." The CEO said other technologies that have changed the world have plateaued; the Robot is just starting.

Tesla's CEO envisions Optimus eventually being like Commander Data, the android from Star Trek the Next Generation, except it "would be programmed to be less robot-like and more friendly." Undoubtedly there is a long way to go to achieve what Doctor Noonien Soong created in Star Trek TNG. What was demonstrated onstage wasn't at that level, but several videos throughout the presentation highlighted what the Robot is capable of at its very early stage in development. The audience watched the Robot pick up boxes, deliver packages, water plants and work at a station at the Tesla factory in Fremont.

Development over 8 Months

The breakdown of some of the systems of the Tesla Robot
The breakdown of some of the systems of the Tesla Robot
Tesla (Edited by Not a Tesla App)

The first Robot to take the stage at AI Day was not Optimus, but Bumble C, another acknowledgement to The Transformers, as Bumble Bee played a significant role in that franchise. However, Bumble C is far less advanced than Optimus, who did appear later but was on a cart.

Several Tesla engineers took turns on the microphone describing some of the most complex elements of the project that was first announced one year ago. Perhaps the best description of the project was the company moving from building a robot on wheels to a robot on legs. However, that may be oversimplifying. For example, the car has two motors, and the Robot has 28 actuators.

Overall Design and Battery Life

Tesla's brightest demonstrated how the production has come to life over the past eight months. It seems this group of computer masterminds had to become anatomist experts as Tesla took hints from the human body to create a humanoid robot. That is an essential factor in creating Optimus. Everything people interact with is made usable by a human, with two legs, two arms, ten fingers etc. If the Robot differed from what the world is already designed for, everything would have to change. However, recreating the human body and its countless movements would take far too long, so Tesla has stripped it down to less than 30 core movements, not including the hand.

Like the human torso contains the heart, the Robot's chest holds the battery. It's projected that a single charge would provide enough for a full day's work with a 2.3-kilowatt-hour battery. All the battery electronics are integrated into a single printed circuit board within the pack. That technology keeps charge management and power distribution all in one place. Tesla used lessons learned from vehicle and energy production to create the battery allowing for streamlined manufacturing and simple and effective cooling methods.

Autopilot Technology

Tesla showed what the Robot sees, and it looked very familiar. That's because the neural networks are pulling directly from Autopilot. Training data had to be collected to show indoor settings and other products not used with the car. Engineers have trained neural networks to identify high-frequency features and key points within the Robot's camera streams, such as a charging station. Tesla has also been using the Autopilot simulator but has integrated it for use with the Robot programming.

Tesla shows off what the Optimus robot sees
Tesla shows off what the Optimus robot sees
Tesla (Edited by Not a Tesla App)

The torso also contains the centralized computer that Tesla says will do everything a human brain does, such as processing vision data, making split-second decisions based on multi-sensory inputs and supporting communications. In addition, the Robot is equipped with wireless connectivity and audio support. Yes, the Robot is going to have conversations, "we really want to have fun, be utilitarian and also be a friend and hang out with you," said Musk.

Motors Mimic Joints

The 28 actuators throughout the Robot's frame are placed where many joints are in the human body. Just one of those actuators was shown lifting a half-tonne nine-foot concert grand piano. There have been thousands of test models run to show how each motor works with the other and how to effectively operate the most relevant actuators for a task. Even the act of walking takes several calculations that the Robot must make in real-time, not only to perform but also appear natural. The robots will be programmed with a locomotion code; the desired path goes to the locomotion planner, which uses trajectories to state estimations, very similar to the human vestibular system.

Human hands can move 300 degrees per second and have tens of thousands of tactile sensors. Hands can manipulate anything in our daily lives, from bulky, heavy items to something delicate. Now Tesla is recreating that with Optimus. Six actuators and 11 degrees of freedom are incorporated into the robot hand. It has an in-hand controller that drives the fingers and receives sensory feedback. The fingers have metallic tendons to allow for flexibility and strength. The hands are being created to allow for a precision grip of small parts and tools.

Responsible Robot Safety

Musk wanted to start AI day with the epic opening scene from Terminator when a robot crushed a skull. He has heard the fears and people warning, "don't go down the terminator path," but the CEO said safety is a top priority. There are safeguards in place, including designs for a localized control ROM that would not be connected to the internet that can turn the Robot off. He sees this as a stop button or remote control.

Musk said the development of Optimus may broaden Tesla's mission statement to include "making the future awesome." He believes the potential is not recognized by most, and it "really boggles the mind." Musk said, "this means a future of abundance. There is no poverty. You can have whatever you want in terms of products and services. It really is a fundamental transformation of civilization as we know it." All of this at a price predicted to be less than $20,000 USD.

Tesla Shows Off its First Robot at AI Day 2

Watch Tesla's AI Day 2 event on demand

By Nuno Cristovao
Tesla to show off its Tesla bot, Optimus tonight
Tesla to show off its Tesla bot, Optimus tonight
Tesla

Tesla is hosting its recruiting event, AI Day 2 tonight in Palo Alto, California.

Elon Musk said to expect a lot of technical detail and "cool" hardware demos. We don't know which demos exactly, although Elon did say the event will be focused on AI and robotics.

Elon also talked about how these events are specifically aimed at showing off the exciting things Tesla is working on to attract more talent.

We can expect Tesla to show off its new Tesla bot, Optimus, talk about FSD and AI and possibly share some details on FSD hardware 4.0 and its upcoming Steam integration.

Start Time

The event took place in Palo Alto, CA on September 30th at 6:15 pm PT.

Watch on Demand

You can watch the event on demand below:

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Although we share official Tesla release notes, we are not affiliated with Tesla Motors. We are Tesla fans and supporters.

Tesla News

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View the release notes for the upcoming version 2022.36.

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Take a look at features that Elon Musk has said will be coming soon.

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