Observation on the selection of cylindrical batteries by car companies

Following BMW's recent acceptance of the new Neue Klasse pure electric vehicle platform, BMW revealed the use of a new cylindrical battery on the Neue Klasse platform. Compared with the square shell battery, the battery cost can be reduced by 30%, and the energy density is higher than the battery currently used by Tesla (from the specification point of view, the change may be caused by the height difference of 10mm). We can think about the current selection of power batteries from the current planning and discussion.

Figure 1. Current status at different stages at home and abroad

In the selection of traditional enterprises, it mainly revolves around the square shell and soft package. At present, the main positions of the two factions are:

1. Square shell

Volkswagen Group (MQB, MEB and standard batteries), Volvo (Gen3 workhorse), Stellantis (European EV), Mercedes-Benz, BMW (pre-Gen5), Toyota, Honda

2. Pouch cell

GM, Ford, Volkswagen Group (before MEB), Volvo (before Gen2), Stellantis, Renault, Nissan, Hyundai-Kia

This time the protagonist is BMW, and the goal is to develop around the next-generation pure electric platform. The 'Neue Klasse' platform takes its name from the Neue Klasse in the 1960s, which marked the beginning of a fundamental change in the direction of BMW's production at the time. BMW also wants to change its development path through this good luck. The main model is around the mid-size car, around the next generation BMW 3 Series and BMW X3 (BMW NK1 and BMW G45) may be the first Neue Klasse platform model, two versions of the new platform Low and High.

The goal of 2025 is actually fundamentally different from BMW’s previous pile of pure electric vehicles. It needs to focus on lower costs and carefully review Tesla’s competitive advantages.

Figure 2 BMW's dedicated platform

This platform mainly uses the electrified powertrain architecture of Gen6, and the entire platform has only one kind of pure electric architecture. The drive is configured as rear-wheel drive (eRWD) and four-wheel drive (eAWD) rear motor + front motor, according to the current disclosure. The efficiency description should be built around SiC technology, and even GaN has been introduced for low-power charging.

Its design may be 800V-based, and it should be designed for a higher fast charging speed (currently 200kW). The 6th generation battery pack consists of higher energy density cells and plans to significantly reduce the use of battery materials by switching to new battery technology, targeting a 30% lower cost than before.

Remarks: One is to use recycled materials, and the other is to reduce the use of cobalt

This will trigger a chain reaction in Europe. We see that Mercedes-Benz is also trying to make a high-power version of the HEV on the AMG sports platform, and it is also trying in parallel in the design of the battery pack. Whether to introduce cylindrical technology, we have to wait for the progress of the two companies. But in this development direction, the biggest temptation is cost, that is, at the moment BMW and Tesla are saying, I want to make cheap batteries with large cylinders, which makes this path need to be carefully evaluated.

Figure 3. Hybrid battery used by Mercedes-Benz AMG

Stellantis is what I'm most curious about because of the current evaluation to develop a low cost standard cylindrical battery. It can be used in all car brands from Fiat to Peugeot, that is, covering two different platforms, small and medium, as shown in the picture below. From the perspective of path and time, this time point will start in 2026, and it will be done around STLA Small - this is also an inevitable choice after the later medium and large platforms are difficult to control the cost.

Figure 4 The adjustable of Stellantis

GM's consideration may be related to this package. Because this bag needs to have a short design, it will be used for a bunch of muscle sports cars in the future, and fast charging must be considered, especially the 800V design. At present, this design will be difficult from the perspective of implementation.

Figure 5. Vertical and stacked arrangement of pouch cells

The next step for Rivian to use a larger cylindrical iron-lithium battery may be the next direction. In its system design, it is also very special to focus on high energy.

Summary: The choice of large cylinders, in fact, with the gradual positioning of the enterprise, the entire climbing speed is quite fast. From the feedback from suppliers, in 2022, Tesla's pulling effect can actually lead to an industry-wide re-discussion and evaluation of the rejuvenation of this technology.