The battery cell format it has become a silent war between the different manufacturers. Although many of them use prismatic or bag-type cells, the cylindrical they seem to be taking the lead. Tesla has always used them, has defended them as the best option to achieve maximum energy density and even seemed to have found the secret formula for it with its latest format: the 4680 cells (46 mm in diameter by 80 mm in height) . Rimac is working on a new battery design that will use cylindrical cells with a diameter greater than 46 mmwith the objective of increase energy density of your future packages.
When Elon Musk announced the new 4680 cells that he is now beginning to produce, he said that they had many advantages. When creating a structural battery pack, this component located on the floor of the vehicle forms part of the resistant structure, which makes it possible to reduce the reinforcement parts and, therefore, the total weight and the production cost. They are also six times more powerful and have an energy capacity five times higher than the 2170. Their larger size multiplies by more than five the volume of active material they can hold and by eliminating the connectors that join each electrode with the battery casing they raise the performance to achieve 16% more autonomy by reducing the weight of the vehicle by 10%
In his presentation, Elon Musk assured that the format had been selected as an optimal limit which reduces production costs without causing problems in charging at high power and without causing difficulties to the thermal management systemwhich occur in the case of the largest cells.
The head of research and advanced engineering at Rimac, Wasim Sarwar Dilovhas just revealed that the Croatian company is working on packages of structural batteries that would be integrated into the car body. Rimac also wants to improve the efficiency of cell-to-package conversion, with the goal that the cells represent the 75% of its total mass. For comparison, the cells of the Porsche Taycan represent 63% of the mass, while in the Tesla Model 3 they represent 64%.
Dilov announces that the Rimac cells they will have varied heights according to their application. While Tesla plans to start manufacturing its own 4680-format battery cells later this year with Panasonic, Samsung aims to manufacture them in South Korea, where it has taken a more flexible approach and offers additional formats with the diameter of 46mm
With the acquisition of Bugatti, Rimac has now become a different manufacturer. “Previously, when we needed them for a few hundred units, we just tried to find the best cells on the market,” says Dilov. “Now that we have significantly increased our production volumes to hundreds of thousands of units, we are in a different era.” Rimac aims to scale the production of this component to no less than 40,000 battery packs in 2023, reaching 200,000 by 2028.
In his day, Yasuaki Takamoto, in charge of the Panasonic Battery Division in the United States, assured that he shared Tesla’s idea of making cells bigger, a key aspect to make electric cars more affordable. However, he did not agree so much on the dimensions chosen by the Californian manufacturer. Takamoto claimed that the larger cells will allow truly affordable electric vehiclessimply because fewer would be needed to power a car, which means a direct reduction in manufacturing costs, although he was highly skeptical about the announced format.