How digital twins are advancing batteries for a greener grid

In institutions and supercomputer labs across Europe, researchers are building something you can’t hold, but which could be key to powering the continent: a virtual replica of a battery for use in energy grids. This "digital twin" is at the heart of the Battery Cell Assembly Twin project (BatCAT) aiming to solve the physical challenges of energy storage by perfecting them in the digital world first.

The project, coordinated by the Norwegian University of Life Sciences (NMBU) and involving 18 European partners, including Simula, is a key part of a continent-wide push to revolutionise battery technology. By creating these sophisticated simulations, BatCAT aims to build better, cheaper, and more durable batteries, resulting in time and cost savings.

Securing Europe’s green energy future

The transition to renewable energy from sources like wind and solar comes with a fundamental challenge: intermittency. The sun doesn’t always shine, and the wind doesn’t always blow, creating a need for massive energy storage systems that can save power for when it’s needed most. This issue is the driving force behind Europe’s strategic focus on battery innovation.

The BATTERY 2030+ initiative
This initiative is about fundamentally reinventing batteries to meet Europe's future energy and environmental needs. It is a long-term research vision to create a new generation of batteries that are more sustainable, safer, and higher-performing than today's technology. 

The initiative's core focus is on accelerating scientific discovery through a "chemistry-neutral" approach, using AI and robotics to find novel materials, and embedding smart functionalities like sensors and self-healing properties directly into battery cells. Ultimately, it is about building a circular battery ecosystem in Europe to drive the green transition and ensure the continent's technological future.

The innovations from BatCAT are aimed at significant societal advantages in pursuit of this goal:

• A stable, renewable-powered grid: Advanced batteries provide the robust, long-duration storage needed to balance the grid, allowing for much greater reliance on solar and wind power and supporting decarbonization efforts.
• Strengthened energy security: By enabling reliable use of domestic renewable energy, these batteries reduce dependence on imported fossil fuels.
• A competitive European industry: By making manufacturing more efficient and accelerating innovation, BatCAT helps build a globally competitive European battery industry, creating jobs and economic growth.

VRFB - Not your typical kind of battery

While most people are familiar with the batteries in their phones and cars, storing energy for an entire city requires a different approach. The basic difference is that a lithium-ion battery is a self-contained device where energy is stored in its solid structure, while a Vanadium Redox Flow Battery (VRFB) stores its energy externally in liquid.

A helpful allegory is to think of a lithium-ion battery like a soda can—the container and the liquid inside are a single, sealed unit. To get more energy, you need more cans. A VRFB, on the other hand, is like a soda fountain. The energy (the syrup) is stored in huge, separate tanks, and the power (the tap) is a separate component. To get more energy, you simply use bigger tanks.

This design makes VRFBs ideal for grid-scale applications. 

The key benefits are that they are safer, with a water-based electrolyte that does not degrade, are simpler to maintain, and have an incredibly long lifespan of over 20,000 charge cycles. VRFBs generate power by pumping the liquid past a special membrane that lets energy transfer between two sides but prevents the liquids from mixing. 

Their widespread adoption has been hindered by challenges like cost and the slow degradation of internal components. Current research focuses on improving the membrane, making the internal parts more durable, and lowering costs. 

Overcoming these hurdles are key to creating a stable and reliable green energy grid for Europe. This is where BatCAT comes in. 

Building the battery in a computer first

The BatCAT project is creating a precise digital twin of the entire VRFB manufacturing process, designed to understand and optimize the system from the molecular level to the complete battery stack.

To capture the battery’s immense complexity, BatCAT employs an advanced multi-scale simulation approach. This digital twin simulates everything simultaneously: from the fundamental interactions of molecules and ions (Molecular Modeling, or MD/MC), to the behavior of the electrolyte (Mesoscopic Modeling, or DPD), all the way up to the performance of the full cell (Continuum Modeling, or FEM/CFD). These physics-based models are then integrated with data-driven machine learning and validated against experimental data from pilot production lines.

At Simula, for example, researchers use this framework to model exactly how energy-carrying vanadium particles move through the system, interact with the battery’s membrane, and how water is transported—all critical factors for performance and durability. This means combining data from the atomic level with system-level performance models and AI-driven "surrogate models" to create one cohesive and interpretable digital twin.

This virtual environment allows the team to test new designs, predict manufacturing defects, and optimize battery performance without the time and expense of building countless physical prototypes. The result is an industrial decision-support system that uses explainable AI to make battery manufacturing smarter, faster, and more reliable.

By leveraging the power of digitalisation, the BatCAT project is improving a battery as well as paving the way for a new paradigm in industrial innovation that holds the potential to ensure Europe's sustainable energy future.

On the BatCAT project website, the team recently shared how they are tackling one of the biggest hurdles in battery production by using real-time process monitoring to fill the gap between lab-scale innovation and reliable industrial manufacturing. Follow the project, towards a future where we can reliably store large amounts of renewable energy, helping to create a more stable and sustainable power grid.

Website: https://www.nmbu.no/en/research/projects/batcat 

This project has received funding from the European Union’s Horizon Europe research and innovation programme under grant agreement No 101137725.