Author: Zhu Yulong

In its latest public announcement, BMW officially declared that it will start using 46-series large cylindrical battery cells in the “NEUE KLASSE 新世代” models from 2025, which marks the transition from the previous five generations of prismatic battery cells. From the current perspective, the significant benefits are:

• 50% reduction in cost target

• 20% increase in energy density and 30% increase in driving range

• 30% reduction in charging time from 10 to 80%

• Both 400V and 800V can be switched and compatible

• High-nickel materials reduce cobalt by 50% and copper by 40%

• Cylindrical battery cells have advantages over other types of batteries in terms of safety, especially in the degradation of the failure mode of a single cell (NP4 discussed by CATL).

The new cylindrical battery cells have a standard diameter of 46mm and two different heights (95mm and 120mm). BMW has signed contracts worth over tens of billions of euros for battery cell production with two cooperative enterprises, Contemporary Amperex Technology (CATL) and EVE Energy, respectively, and will establish two battery cell factories in China and Europe, with an annual production capacity of 20 GWh for each factory. BMW is also seeking a partner in the North American Free Trade Area to build two more battery cell factories.

This evolution has changed the overall demand for future battery cells since the monopoly of prismatic battery cells. I think the key is that in addition to its strong supporter, Tesla, another influential automaker, BMW, who used to be a prismatic expert, has switched to cylindrical battery cells, which has given other automakers who choose cylindrical battery cells more confidence.

BMW’s design choice

In fact, at first, it was rumored that the next-generation BMW battery (GEN6) would change its shape, replacing the current prismatic battery with cylindrical battery cells, which surprised everyone. This German carmaker has always been a firm supporter of prismatic batteries and has never used pouches to make battery electric vehicles (BEVs). However, they have made a big change, planning to introduce these new batteries into BMW models from 2025. We can observe the two-generation batteries and share with you what we have learned.

According to the current disclosure, GEN6 battery cells will be developed in two sizes, with a diameter of 46mm and heights of 95 or 120mm, respectively targeting sedans and SUVs, depending on the need for Z-axis height of the vehicle. The sixth-generation battery technology will use lithium iron phosphate (LFP), which is also intended to be like Tesla.

Note: In Tesla, there are also two factions, one is to use different chemical systems to solve different capacity requirements for 4680, and the other is to iterate around Pack with prismatic and blade.What are the advantages of large cylindrical batteries for BMW’s electric vehicles? For this new generation of batteries, BMW believes that cylindrical battery cells will bring several benefits:

• Better integration
• Better energy density
• More sustainable solution
• Increased safety

In terms of suppliers, Chinese power battery companies still have the upper hand in large cylindrical batteries, with 80 GWh out of 120 GWh being held by them, but EVE Energy has also secured similar orders to CATL.

In the current expansion, around the 46 series, two heights (95 mm and 120 mm) are being developed for SUVs and sedans, and developing LFP and high-nickel products is a good attempt. The nickel content in the positive electrode material is higher, and the cobalt content is lower. The silicon content in the negative electrode is higher, which can improve the energy density by 20%.

BMW has established a trial production line at its cell manufacturing center in Parsdorf near Munich, with commissioning work starting later in 2022. Once perfected, the large cylindrical production lines and methods will be implemented at the supplier’s new factories, preparing for the launch of the NEUE KLASSE model in 2025.

In the module design of Gen5 shell-type batteries, BMW adopts a double-row module format, iterating to the entire pack or even CTC design in the new era of 46 cylindrical battery cells.

In this design, BMW focuses on the cell design while isolating the supplier at the cell level. Its engineers are mainly responsible for the system-level pack design, allowing BMW to achieve differentiation. This approach is very aggressive for BMW in the next generation of designs and is similar to that of Tesla.

Discussion on Strategic Goals

Currently, battery selection is not just about technology, it is a sustainable choice. How to do this in the face of ultra-high penetration rates? BMW’s choice is not to build its own battery factory, but to invest in battery cell companies for layout and cost control.

On the one hand, BMW comprehensively improves the level of its own battery cells and achieves standardization of battery cells. The strategy emphasizes having multiple suppliers to ensure consistency and reduce patent barriers. Otherwise, it would be difficult to have multiple suppliers due to patent barriers at the battery cell level. On the other hand, BMW promotes its own Know How and external collaboration in valuable aspects, which is also the core reason why BMW invested in the Battery Cell Competence Center and pilot production lines before.

Furthermore, BMW aims to achieve rapid advancement in the platformization of the electric vehicle’s three-electric system. This is consistent with Tesla’s strategic goals and can be achieved on a large scale only through standardization without entering the battery manufacturing field. Essentially, Tesla drives suppliers by doing its own production of the 4680 battery cell. Now, the two sides have some synergy.

In conclusion, for automakers, it is most important to allow enough suppliers to invest, spend money on production capacity, and maintain low profits to supply. Standardizing batteries can actually achieve lower cost control than making battery cells yourself. There is no other supplier that can step up in the casing industry, this is a certainty, so it is necessary to open up a new path.

This article is a translation by ChatGPT of a Chinese report from 42HOW. If you have any questions about it, please email bd@42how.com.