Back in June I wrote about Tesla’s plan for a “Battery Day” event at which they were expected to announce some significant improvements to the design of the batteries used in their cars and Powerwalls. That event was initially scheduled for the spring but was pushed back because of the coronavirus. Today is normally the day Tesla reports on its quarterly production number and that is still happening but it is now being overshadowed by Battery Day.

So what is the company going to announce today? No one outside the company knows exactly. Back in the spring, Reuters reported that the company had made improvements to battery design which made battery cells last longer before they degrade from repeated cycles of charging and discharging. This “million mile battery” was so named because it could last long enough to take a car a million miles before the cells needed to be replace, much longer than most cars last. The idea has been described as the promise of a “lifetime car.”

But there are also some expectations that the announcement today could go beyond that, possibly to some additional improvements in battery tech that hasn’t already leaked to the media. In fact, Elon Musk promised “exciting things.”

Many exciting things will be unveiled on Battery Day 9/22 ⚡️

— Elon Musk (@elonmusk) September 11, 2020

But just last night he seemed to be trying to dial back expectations a bit, noting that whatever gets announced won’t be mass produced for another couple of years.

Important note about Tesla Battery Day unveil tomorrow. This affects long-term production, especially Semi, Cybertruck & Roadster, but what we announce will not reach serious high-volume production until 2022.

— Elon Musk (@elonmusk) September 21, 2020

The extreme difficulty of scaling production of new technology is not well understood. It’s 1000% to 10,000% harder than making a few prototypes. The machine that makes the machine is vastly harder than the machine itself.

— Elon Musk (@elonmusk) September 22, 2020

Nevertheless, today could be a big deal in trying to solidify America’s lead in battery tech. At present, it is actually Japan that has been filing the most patents. The U.S. is currently in 5th place:

Ahead of nothing in particular (cough), new study says U.S. in fifth place behind Japan, South Korea, Europe and China in terms of the number of international patents in battery technology. https://t.co/f3ujTQsXdc pic.twitter.com/eqz6fT87bS

— Steve Goldstein (@MKTWgoldstein) September 22, 2020

But that chart doesn’t tell the whole story:

One area the U.S. is strong in is potential next-generation batteries, the study says. The U.S. is the leader with 36% of patents on lithium-nickel-cobalt-aluminum-oxide chemistry for Li-ion batteries, which are already being used by Panasonic and Tesla.

Tesla’s main goal is not only to make the batteries last longer but to make them cheaper to produce. Until that happens the only way electric cars can compete with gasoline powered cars is with government subsidies. Musk’s goal has been to get the cost of batteries under $100 per kilowatt hour. If he can do that, electric cars become much more competitive in the marketplace. One of the efforts Tesla has been pursuing is to make the battery cells cheaper to produce by limiting or possibly even removing the need for cobalt:

Musk has been vocal about wanting to eliminate cobalt from Tesla’s batteries. In 2018, he tweeted that Tesla uses less than 3 percent of cobalt in its batteries and that the next-generation versions would have “none.” Battery Day could be an opportunity for the company’s CEO to outline exactly how he could achieve that.

Cobalt is a key component of batteries. It’s also the most expensive material in the battery and mined under conditions that often violate human rights, leading it to be called the “blood diamond of batteries.” As a result, scientists and startups are rushing to create a cobalt-free battery.

Finally, Tesla now has some challengers in the electric car market including one which just released its first sedan this month with specs a bit better than the Model S. So today’s announcement could also help keep Tesla positioned at the front of the pack in the mind of potential buyers.

The livestream of the Battery Day event will began at 4:30 pm on the east coast, 1:30 here in the west. You can watch it here. I’ll be back later with a summary of the big announcements:

Update: I did watch the full Battery Day presentation and it was a very detailed description of all of the changes Tesla is making to battery design, materials, etc. to make these cells better and cheaper. Forbes has a pretty good summary of the news:

1. A 56% total reduction in cost per kwh of the battery pack — massive.
2. A resulting 54% increase in range for the same size pack.
3. Significant reduction in footprint of factories and cost of scaling up production — 69% less investment needed
4. Silicon anodes with higher capacity
5. New cobalt-free anodes, including very high capacity all nickel cathodes
6. Major improvements to the processing part of cathode manufacturing
7. New sources of immense supplies of Lithium
8. Making the structural rear of the car from a single casting
9. Making the battery pack a structural element in the car, effectively making it add no weight to the car
10. A $25,000 quality EV in 3 years with autonomy capability

Because of the level of detail provided each one of those points could be a story in itself but one of the details about the new tabless battery design:

Today, the company confirmed that the new cell is 46mm by 80mm, giving it its name: the Tesla 4680 battery cell.

The company faced the same problem as anyone who tries to increase capacity by making a bigger cell. They have a thermal management program.

As previously reported, Tesla fixed this issue by creating the first tabless cylindrical cell design…

Tesla claims that the new form factor of the cell results in a five-times increase in energy and six-times increase in power capacity.

Here’s what it looks like from the top down:

#BatteryDay @Tesla revealed a tables battery cell design, getting rid of tabs allows for dramatic simplifications in production efficiency. Resulting in much better thermal effects.

pilot 10GWh production facility launched. It will take about 1 year to reach full capacity. pic.twitter.com/RKqupvZSTV

— Dreams of Mars 2049 (@MemesOfMars) September 22, 2020