Electric vehicle batteries may soon be able to charge more quickly and last longer through a groundbreaking approach that creates a virtual replica of the battery’s internal structure.
At the Korea Advanced Institute of Science and Technology (KAIST), scientists developed a three-dimensional “digital twin” of a commercial lithium-ion battery electrode. Their research, featured in the journal InfoMat, highlights that battery performance is influenced not only by the materials inside the electrode but also by the precise placement of those materials.
Fast charging remains one of the biggest hurdles for electric vehicles. Consumers want to recharge their cars within minutes instead of hours. However, pushing lithium ions into a battery at a high rate can cause damage and reduce its lifespan.
A typical lithium-ion battery’s graphite anode contains graphite particles that store lithium, along with a binder that holds these particles together and tiny pores filled with electrolyte. During charging, lithium ions move through the electrolyte and enter the graphite. When charging occurs too rapidly, some lithium ions can’t enter the graphite fast enough and instead form metallic lithium deposits on the surface—a process known as lithium plating, which can harm the battery.
Think of it like a traffic jam at a parking lot entrance: if too many cars arrive simultaneously and can’t get in, congestion builds up outside. Meanwhile, other changes happen inside the battery: a protective layer called the solid electrolyte interphase (SEI) forms on graphite particles. While a thin SEI is necessary, if it becomes too thick or uneven, it hampers battery performance. Additionally, as graphite particles absorb lithium, they expand, creating mechanical stress within the electrode. Since these processes occur at microscopic scales, pinpointing where issues develop is challenging.
To better understand these microscopic dynamics, researchers led by Professor Kang Taek Lee reconstructed a real graphite anode in 3D. This digital model included individual graphite particles, binder material, and the pores through which lithium ions travel. They then simulated various conditions—altering electrode thickness, pore sizes, and binder distribution—to see how these factors affect fast charging.
The findings revealed that the arrangement of binder material inside the electrode can have a significant impact. For a 50-micrometer-thick anode, different binder placements resulted in less than a 4% variation in overall charging capacity—differences so slight that traditional tests might overlook them. However, beneath the surface, the internal differences were substantial.
When excess binder accumulated near the separator, it restricted pathways for lithium ions, creating traffic-like bottlenecks. This led to over 10% more lithium plating in some regions compared to electrodes with a more uniform binder distribution. Properly distributed binder allowed lithium ions to flow smoothly and helped form a more even SEI layer, which is essential for battery health.
These effects became even more pronounced in thicker electrodes—say, an 83-micrometer anode—where variations in binder placement caused about an 18% difference in charging capacity. The placement of pores also mattered: regions with more open space could better accommodate the expansion of graphite particles, reducing mechanical stress, whereas tightly packed areas experienced more strain.
The study suggests that future electric vehicle batteries should be designed with a microscopic level of precision. Instead of just selecting how much graphite, binder, or pore space to include, engineers need to carefully control where these materials are located. Digital twin technology offers an efficient way to virtually test different internal arrangements before manufacturing, potentially accelerating the development of batteries that can charge faster, store more energy, and last longer.
