Tesla has been quite secretive about its latest generation of battery cells, the 2170 li-ion cells, which they designed for Model 3 and Panasonic is manufacturing them at Tesla’s Gigafactory 1 in Nevada.

The company has now released rare details about the battery cells – claiming the highest energy density on the market and the use of less cobalt.

Since its inception, Tesla has been using 18650 battery cells made by Panasonic, but Tesla works with the Japanese manufacturer to tune the chemistry of the cells, which make them unique and not exactly off-the-shelves.

For Model 3, Tesla designed the Model 3 battery pack architecture around a new bigger 2170 cell format and worked with Panasonic to build the cells with a new chemistry at Tesla’s Gigafactory 1 in Nevada.

They started production in June 2017 and at the time, not much was known about the cells.

In Tesla’s shareholder’s letter published yesterday, the company released some rare details about Model 3’s battery cells. They wrote:

“Cells used in Model 3 are the highest energy density cells used in any electric vehicle. We have achieved this by significantly reducing cobalt content per battery pack while increasing nickel content and still maintaining superior thermal stability. The cobalt content of our Nickel-Cobalt-Aluminum cathode chemistry is already lower than next-generation cathodes that will be made by other cell producers with a Nickel-Manganese-Cobalt ratio of 8:1:1. As a result, even with its battery, the gross weight of Model 3 is on par with its gasoline-powered counterparts.”

The automaker has been claiming the highest energy density before the cells even went into production, but it’s still not supported by strong number.

People claiming to have done teardowns of the Model 3 pack and tested the cells have claimed an energy capacity from 5,750 to 6,000 mAh, but it still unconfirmed at this point.

As for the mention of cobalt, Tesla is releasing this achievement of reducing the amount of the metal in the Model 3 cell’s cathode as cobalt prices have more than doubled over the last year.

Demand for cobalt has increased significantly over the last few years since it is used in several different types of battery cell chemistry and the demand for battery cells has greatly increased due to the rise of electric vehicle and energy storage systems.

Tesla CTO JB Straubel added that they have seen the trend coming and have been “on a path to reduce cobalt usage for several years now.” He says that it is starting to help with the cost.

Speaking of cost, Tesla still refused to confirm where they are on the range of cost per kWh, but CFO Deepak Ahuja said that based on their internal data, they think they are “the best in class in terms of cost per kWh.” Tesla CEO Elon Musk then clarified that they believe that they have the best cost period.

As we reported yesterday, battery cost is extremely important and not just for Model 3. The Tesla Semi also appears to require a significant improvement in battery cost in order for its price point to be achievable.

Last year, electric vehicle battery cost dropped down to $227/kWh, according to a report. Tesla claimed to be “below $190/kWh” at the time. We estimate that it would need to be below $100/kWh to enable the price of the Tesla Semi and it will also help Tesla be profitable with the Model 3.

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