Summary
- Before charging an EV for the first time, controlled charging cycles occur in the factory
- Toyota-funded study found that high currents during initial charging phases improve battery performance and lifespan
- Charging lithium-ion batteries at high speeds for the first time can extend lifespan by up to 70%
- The initial charging cycles stabilize the battery pack, impacting performance, longevity, and quality
- New technique of high initial current charging can improve battery performance and lifespan
Article
A study funded by the Toyota Research Institute has discovered a novel way to boost EV battery health and minimize degradation by charging lithium-ion batteries for the very first time at unusually high speeds. This approach extends battery lifespan by an average of 50% and up to a maximum of 70%. The research, published in the scientific journal Joule, highlighted the critical step in battery manufacturing called “formation”, where the initial charging and discharging cycles take place to stabilize the battery pack and activate the materials within the cells. This process impacts the battery’s performance, longevity, and overall quality, similar to tuning a musical instrument before a performance. The SLAC-Stanford Battery Center conducted the study in collaboration with other institutions, running 186 charging and discharging cycles across 62 formation protocols to test the effects of high current charging on battery health.
The initial charging cycles play a crucial role in battery manufacturing, influencing the outcome in terms of performance and longevity. Traditionally, manufacturers give batteries their first charge with low current, which is time-consuming and a primary bottleneck in battery production. Without proper formation, a battery may not function as intended, making it an essential aspect of production. However, the new technique discovered in the study involves pumping high current into the pack for the very first time, causing the cells to lose some lithium content, which is then used to form a protective layer on the negative electrode during the first charge. This layer helps improve the pack’s lifespan by protecting the negative electrode from accelerated lithium loss over time.
The study’s findings contradict existing notions about lithium-iron phosphate (LFP) battery charging practices, suggesting that consistently using LFP batteries at a higher state of charge can negatively affect battery health and degradation. The research demonstrates that high formation charge current on the first cycle can extend battery cycle life by an average of 50%, highlighting the importance of the initial charging process in maximizing battery performance and longevity. By utilizing this new technique, manufacturers could potentially save time and extend the age of EV batteries, as the additional headspace created in both electrodes helps improve battery performance and lifespan.
The battery scientists involved in the research project include researchers from the SLAC-Stanford Battery Center, Toyota Research Institute, the Massachusetts Institute of Technology, and the University of Washington. Together, they conducted a thorough investigation into the effects of high current charging on EV battery health and discovered that this approach can significantly enhance battery performance and extend lifespan. This research is part of the Accelerated Materials Design and Discovery program funded by the Toyota Research Institute, which aims to explore innovative ways to improve battery technology and enhance the sustainability of electric vehicles. Overall, the study’s findings highlight the importance of the initial charging process in shaping battery health and longevity, offering new insights into optimizing EV battery performance.
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