In the realm of energy storage, a team of researchers from the University of Oxford, led by Joseph Ross and including Damien Frost, Stratos Chatzinikolaou, Stephen Duncan, and David Howey, has been delving into the challenges posed by large battery systems. Their recent study, published in the journal Applied Energy, focuses on the issue of heterogeneous currents and temperatures in modules with parallel-connected cells, a common setup in grid storage systems.
The researchers set out to quantify these imbalances through a combination of simulations and experiments on an industrially representative grid storage battery module. The module in question consisted of prismatic lithium iron phosphate cells, a type commonly used in grid storage applications. The team’s goal was to understand the evolution of current and temperature imbalances and their dependence on individual cell and module parameter variations.
Through their work, the researchers found that varying contact resistances and cell resistances contribute significantly to temperature differences between cells. This led them to define safety thresholds on cell-to-cell variability, which are crucial for ensuring the performance and longevity of battery systems. The team also investigated how these thresholds change for different applications, outlining a set of robustness metrics. These metrics show that cycling at lower C-rates (a measure of the rate at which a battery is charged or discharged) and narrower state of charge (SOC) ranges can help mitigate failures.
The practical implications of this research are significant for the energy sector. Understanding and managing current and temperature imbalances in battery modules can lead to more efficient and reliable grid storage systems. This, in turn, can support the integration of renewable energy sources, which often require storage solutions to manage intermittency. By providing clear guidelines on operating conditions, the research can help extend the lifespan of battery systems, reducing costs and environmental impact.
In summary, the study by Ross and colleagues sheds light on a critical aspect of battery management in grid storage systems. By quantifying imbalances and defining safety thresholds, the research offers valuable insights for improving the performance and longevity of energy storage solutions. This work is a step forward in the ongoing effort to optimize battery technology for a more sustainable energy future.
This article is based on research available at arXiv.