Pouch, Cylindrical or Prismatic: Which Battery Format Will Rule the Market?
When we talk about battery format, we talk about three main forms: cylindrical, prismatic and pouch cells. With their cylindrical shape and build, cylindrical cells are one of the first types of mass-produced batteries and to this day continue to be made in high volumes and dominate certain applications. On the other hand, prismatic cells gained popularity due to their large capacity, thin profile and effective use of space. Their prismatic shape makes it easy to connect multiple cells together, creating a bigger battery pack. Finally, pouch cells, with their sealed flexible foil acting as the container, are known for having a more lightweight structure.
Whilst each type of battery cell is better suited to different situations, the cylindrical cell has proven to be the most convenient and adaptable in many ways despite its limits. However, pouch cell usage is growing thanks to its flexibility and overall optimization, and is set to dominate the automotive market.
In 2020, the total usage in the passenger vehicle market was ~147 GWh for ~$17B. The market share split was: prismatic ~40%, pouch ~35% and cylindrical ~15%, based on the top 6: LG, CATL, Panasonic, Samsung, BYD and SKI. The remaining 10% from the Tier 2 players may also be split within the three formats.
The cylindrical cell
According to a recent report, the global Cylindrical Lithium Ion Battery market was valued at the US $7975.1 million in 2019.
With its high mechanical stability and design, the cylindrical cell is mostly produced with optimized automation processes and techniques, increasing consistency and lowering the cost per unit. Indeed, many manufacturers can provide this type of battery cell which creates product uniformity. That means that if a business’ supplier cannot deliver for any reason, they are sure to find another one producing the same product in terms of performance and dimensions. This makes it easier to switch.
However, due to its shape, it is not possible to fully utilize the space available in the battery pack, leading to the lower packing density of the cylindrical cell.This is why cylindrical cells have reached their limit in terms of performance and optimization, resulting in questions being raised about them being potential for next-generation batteries.
Photo credit: Crystal Kwok, Unsplash
An additional limitation is that you need a much larger cell count: even with a 4680 with ~25 Ah capacity, as Tesla presented last year, the cell count is 4 times that of a 100 Ah flat cell for the same pack capacity which in turn increases the overhead for BMS, TMS, etc.
The prismatic cell
Used mainly in consumer electronics and EVs, the prismatic cell’s packing advantages lie in its layered approach to materials. Their shape resembles a box of chewing gum or a small chocolate bar and though they exist in different sizes, there is no universal format and each manufacturer designs its own.
The pouch cell
The soft aluminium coating allows for a more lightweight battery and depending on the use, an adaptable size and available space. This leads to flexible cells that can easily fit the available space of a given product. In terms of space optimization, this translates to between 90%-95% packaging efficiency and increased energy density. By moving to more convenient designs, pouch cells have the potential to match the next-generation performance batteries to accelerate the electrification needs of EVs and consumer electronics.
For example, in Tesla’s first EV, they used many cylindrical cells at the same time to get a lot of energy at a low cost. Indeed, Tesla bought cheap batteries, which are a commodity (18650 cylindrical by Panasonic) and used a lot of them connected with a very high-quality battery management system (energy management software).
An outstanding limitation of the pouch cell format lies in the lack of standardization, impacting costs to produce and selling prices. As the development of the pouch cell continues, it will become more available, adoption will increase and it will be more widely used. Indeed, standardization will improve production, efficiency, lower costs and increase volumes all whilst optimizing performance.
Additionally, the pouch cell still has some optimization to do as it has lower mechanical resistance and can suffer from potential expansion due to ageing caused by gas development.
Whilst the cylindrical cell has come to a point where it reached its limit in increasing energy density, it won’t disappear from the market either. Instead, the pouch cell will have a more dominant stake in the battery market, especially once more development and investment have been put in and it becomes more mass-produced.
Pouch cells are also set to be used the most because the battery considered to be the holy grail of EV batteries, solid-state, can only work in the pouch cell format. Therefore as solid-state is commercialized, with experts talking about 2025-2030, it will be embraced by the industry, meaning that batteries will be adapted to the pouch format.
Looking forward, it appears that as the pouch cell is optimized and moves to higher volume production, flat formats (pouch and prismatic) will be the most used, especially for automotive and energy storage use.
Photo credit: Matt Henry, Unsplash
Battery formats and new 3D architecture technologies
Addionics’ unique technology is compatible with all formats, improves mechanical stability by embedding layers and has additional benefits for pouch cells. Therefore, it makes sense to dedicate additional attention to the pouch cell as it benefits the most from Addionics and is also one of the dominant formats for next-generation batteries. This combined with the natural abilities of pouch cells ensures for one of the most adaptable and powerful batteries on the market.
Additionally, Addionics’ technology is currently embedded in pouch cell batteries in three different chemistries: LFP (lithium iron phosphate), silicon and solid-state, and is also compatible with other formats.