Approach developed to reduce EV battery testing time

University of Michigan researchers have developed a system for electric vehicle (EV) batteries designed to save time and money.

By Jim Lynch June 30, 2022
卢伟是密歇根大学机械工程教授,在卢实验室循环电池。照片:布伦达Ahearn)。由密歇根大学提供。

Testing the longevity of new electric vehicle battery designs could be four times faster with a streamlined approach, researchers at the University of Michigan have shown.

Their optimization framework could drastically reduce the cost of assessing how battery configurations will perform over the long haul.

“The goal is to design a better battery and, traditionally, the industry has tried to do that using trial and error testing,” said Wei Lu, U-M professor of mechanical engineering and leader of the research team behind the framework, published in Patterns-Cell Press. “It takes such a long time to evaluate.”

卢伟是密歇根大学机械工程教授,在卢实验室循环电池。照片:布伦达Ahearn)。由密歇根大学提供。

卢伟是密歇根大学机械工程教授,在卢实验室循环电池。照片:布伦达Ahearn)。由密歇根大学提供。

随着电动汽车电池制造商疲于应对续航里程焦虑和充电可用性问题,卢勇团队开发的优化系统可以将新型更好电池的模拟和物理测试时间缩短约75%。电池研发人员正在寻找合适的材料和配置组合,以确保消费者始终有足够的容量到达目的地,这样的速度可能会给他们带来很大的推动。

Parameters involved in battery design include everything from the materials used to the thickness of the electrodes to the size of the particles in the electrode and more. Testing each configuration usually means several months of fully charging and then fully discharging—or cycling the battery—1,000 times to mimic a decade of use. It is extremely time-consuming to repeat this test through the huge number of possible battery designs to discover the better ones.

“我们的方法不仅减少了测试时间,还能自动生成更好的设计,”卢说。“我们使用早期反馈来丢弃没有前途的电池配置,而不是循环使用到最后。这不是一项简单的任务,因为在早期周期中性能一般的电池配置可能会在后期表现良好,反之亦然。

“We have formulated the early-stopping process systematically and enabled the system to learn from the accumulated data to yield new promising configurations.”

To get a sizable reduction in the time and cost, U-M engineers harnessed the latest in machine learning to create a system that knows both when to quit and how to get better as it goes.

The framework halts cycling tests that don’t get off to promising starts in order to save resources using the mathematical techniques known as Asynchronous Successive Halving Algorithm and Hyperband. Meanwhile, it takes data from previous tests and suggests new sets of promising parameters to investigate using Tree of Parzen Estimators.

Colton Rainey, a PhD student in mechanical engineering makes batteries at the Lu Lab. Photo: Brenda Ahearn. Courtesy: University of Michigan.

Colton Rainey, a PhD student in mechanical engineering makes batteries at the Lu Lab. Photo: Brenda Ahearn. Courtesy: University of Michigan.

In addition to cutting off tests that lack promise, a key time-saving element in U-M’s system is the way it generates multiple battery configurations to be tested at the same time, known as asynchronous parallelization. If any configuration completes testing or is discarded, the algorithm immediately calculates a new configuration to test without the need to wait for the results of other tests.

U-M’s framework is effective in testing designs of all battery types, from those used for decades to run internal combustion automobiles, to the smaller products that power our watches and cell phones. But EV batteries may represent the most pressing use of the technology.

“This framework can be tuned to be more efficient when a performance prediction model is incorporated,” said Changyu Deng, U-M doctoral student in mechanical engineering and first author of the paper. “We expect this work to inspire improved methods that lead us to optimal batteries to make better EVs and other life-improving devices.”

A recentsurveyconducted by Mobility Consumer Index showed 52% of consumers are now considering an EV for their next vehicle purchase. Despite changing attitudes, concerns remain over vehicle range (battery capacity) and the number of charging stations available to drivers.

Battery performance, therefore, has a central role in bringing EVs to the masses as a means of offsetting the impacts of climate change.

“By significantly reducing the testing time, we hope our system can help speed up the development of better batteries, accelerate the adoption or certification of batteries for various applications, and expedite the quantification of model parameters for battery management systems,” Lu said.

– Edited from aUniversity of Michigan文章来自CFE媒体与技术。


Jim Lynch



Author Bio:University of Michigan