The design of the Tesla Semi battery pack has leaked, and it reveals how Tesla fits a massive ~900 kWh pack in the truck.

Tesla unveiled the production version of its Tesla Semi class 8 electric truck and delivered the first units last month.

At an event, Tesla described an electric truck that could truly disrupt the trucking industry.

However, we noted that there were a few pieces of information that Tesla omitted from the event that could really make a significant difference in the usefulness of the truck.

The two main missing pieces of information were the battery pack capacity and the weight of the tractor. Weight determines the load capacity since total weight with load and trailer is limited to 82,000 lbs.

More recently, CEO Elon Musk released a few details that allow us to confirm that the Tesla Semi battery pack has an energy capacity of about 900 kWh.

The battery pack has never really been visible on the Tesla Semi prototypes. Frankly, that’s impressive because how do you hide almost 1 MWh pack inside a vehicle like that?

Now thanks to Tesla hacker Green the Only, we get our first look at the Tesla Semi battery pack design and other important components:

The images appear to be from the parts catalog for the Tesla Semi. It singles out the components including the battery pack.

It also confirms that the Tesla Semi battery pack is located underneath the cabin at the base of the vehicle:

That’s not unusual for Tesla vehicles as the automaker attempts to keep the center of gravity low.

However, the pack design itself is quite different from anything else we have seen before.

It appears to feature nine large modules with two different sizes. The ones in the middle appear significantly larger than the ones on the sides of the vehicle.

The modules are also much taller than any other Tesla battery pack, which previously only were the height of one row of battery cells plus hardware.

Now, it looks more like the Tesla’s old Model S battery modules being stacked together:

There are a lot of unanswered questions about the Tesla Semi battery. For example, we still don’t know for sure what cell Tesla is using in the truck.

It was believed that the automaker would use its own 4680 cells, but CEO Elon Musk indicated that this wouldn’t necessarily be the case.