In today's rapidly evolving market for energy storage solutions, prismatic cells are emerging as a groundbreaking innovation in battery technology, offering a tailored design and unique advantages that are reshaping the industry landscape. From the characteristics of prismatic cells to their advantages, OEMs including Volkswagen’s PowerCo have started to develop these batteries. While prismatic cells still face certain challenges, how can they be improved using Addionics’ technology?
About Prismatic Cells
While lithium batteries are always made of cells, in today’s market, two main types of cells exist: cylindrical and prismatic, which are named after their shape. Prismatic cells represent a distinct form of lithium-ion battery, characterized by their flat and rectangular shapes. Unlike cylindrical cells, prismatic cells are tailored to fit specific applications, with everything inside neatly sandwiched into layers and encased in materials like steel or aluminum. The use of insulated film further enhances safety and protection. Additionally, prismatic cells make internal use of winding or lamination processes. Notably, prismatic cells offer superior space efficiency, making them a preferred choice for EVs where maximizing storage within limited confines is essential.
The Advantages of Prismatic Cells
Prismatic cells stand out in the world of battery technology due to their unique advantages, prominently showcased by their large capacity and distinctive prismatic shape, which facilitates the connection within applications. Unlike cylindrical cells, prismatic cells boast larger sizes and fewer connections, enabling them to accommodate larger capacities.
The energy density of prismatic cells can surpass that of cylindrical cells, thanks to their simpler structure and production process, which doesn’t require the use of high-strength stainless steel shells. Additionally, prismatic cells showcase more optimized thermal characteristics, requiring less cooling per energy unit and offering higher cycle life expectancies even under high and varied loads. This makes them a more cost-effective option for applications including EVs. Furthermore, with a space-efficient design and stackability, prismatic cells allow for the creation of battery packs with higher energy density and enhanced thermal performance.
The Challenges
While prismatic cells offer notable advantages, some limitations also need to be considered. Indeed, compared to cylindrical cells, which can be produced at a much faster rate, prismatic cells face challenges in terms of production efficiency, resulting in higher costs per kilowatt-hour produced. One significant drawback of prismatic cells lies in their internal structure, where positive and negative electrodes are sandwiched together, increasing the risk of short circuits and swelling. This complexity poses difficulties for Battery Management Systems to adequately protect each cell from overcharging and heat dissipation, especially given the larger capacity of prismatic cells. Moreover, the larger size of prismatic cells limits automation possibilities, leading to a lower degree of manufacturing consistency and increased susceptibility to deformation and swelling.
The pointed corners inherent to prismatic cell shapes present another concern, as they are more prone to stress, shocks, and vibrations, potentially weakening the cell integrity if not adequately protected. Additionally, the absence of a universal format for prismatic cells complicates standardization and increases the need for custom builds, resulting in higher costs, minimum order quantities, and certification requirements for customers. Furthermore, the stacking configuration of prismatic cells, typically in series, restricts airflow between cells, hindering heat dissipation and potentially exacerbating thermal management issues. Lastly, the impact of a single faulty cell within a prismatic cell pack can be more severe compared to cylindrical cell packs, where the impact is mitigated by the pack's design and multiple connections.
Prismatic Cells in on the Market
PowerCo, a Volkswagen subsidiary, is planning to start manufacturing prismatic cells at battery production plants in Europe and North America. Scheduled to begin in 2025, more than €20 billion has so far been allocated to their development up to 2023. Moreover, these cells are expected to be used in 80% of all Volkswagen EVs. Indeed, these prismatic batteries will have three main chemistries: LFP for entry-level EVs, a ternary cell based on manganese for high-volume EVs, and ternary nickel-rich batteries with more energy density for high-end EVs. This will allow different EV types to benefit from these cells, as well as various battery chemistries. Furthermore, these cells are being designed to be compatible with existing EV models.
7 Ways that Addionics Improves Prismatic Cell Performance
Combining prismatic cells with Addionics’ Smart 3D Current Collectors provides multiple qualities that can enhance the overall performance and reliability of this type of battery, and lead to the acceleration of their adoption. Indeed, depending on the design, materials, and manufacturing processes used, the benefits and performance improvements achieved with 3D porous current collectors can include:
Improved Electrode-Current Collector Interface
The current collector's 3D porous architecture offers a larger surface area for depositing electrode material, resulting in better contact between the active material and the current collector. This improved interface enhances electron transfer kinetics as well as overall battery performance.
Enhanced Electrolyte Penetration
The porous structure of the 3D current collectors enables improved electrolyte penetration across the electrode, fostering uniform ion transport and distribution. This leads to improved electrochemical reactions and enhanced battery efficiency.
Enhanced Mechanical Stability
The 3D current collector's porous framework offers mechanical support to the electrode material, reducing the risk of mechanical failure such as cracking or delamination. This results in improved structural stability and longevity of the battery.
Improved Thermal Management
The open and interconnected pores of the 3D current collector enable efficient heat dissipation during battery operation. This helps to mitigate temperature gradients within the battery, reducing the risk of thermal runaway and improving overall safety.
Increased Active Material Loading
The porous current collector's 3D configuration enables greater loading of active materials, leading to increased energy density and capacity of the battery. This results in improved energy storage capabilities and extended battery runtime.
Enhanced Cycling Stability
The porous structure of the 3D current collector contributes to alleviating the stress and strain on the electrode material throughout charge-discharge cycles. Consequently, this improves cycling stability and leads to a longer battery lifespan, making it suitable for applications requiring high cycle life.
Facilitates Fast Charge/Discharge Rates
The improved electrode-electrolyte interface and enhanced ion transport facilitated by the 3D porous current collector enable faster charge and discharge rates. This makes the battery suitable for high-power applications that require rapid energy delivery.
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