Develop Lightweight, Low-temperature, and Safe Batteries for Autonomous Electric Vehicles

Principal Investigator

• Chengcheng Fang, Wolfgang Bauer (co-PI), Michigan State University

Faculty

• Mahmood Haq, Satish Udpa, Michigan State University

Student

• Dang Nguyen, Robert Kuphal, Michigan State University

Government

• Yeefeng Ruan, Vamshi M Korivi, US Army GVSC

Project began Q4 2022.

Battery packs provide power for electric vehicles (EVs). The weight of battery packs in an EV can reach 25% of the total weight, making EVs 10 - 15% heavier than gasoline-based cars. The heavy weight not only decreases the EV’s dynamic and braking characteristics, but also reduces the mileages that batteries can power. The battery energy density (Wh/kg) needs to be improved to reduce the weight of battery packs while maintaining or even increasing the mileages per charge. For Army application, batteries further require adaptability under unpredictable extreme conditions: batteries need to be operational under extreme cold weather; battery thermal runaway, which causes explosion, needs to be prevented at high temperature conditions, and during accidents such as crashing and shooting.

The overall research objectives of this project are to develop lightweight, low-temperature capable, and safe EV battery packs. The lightweight objective is equivalent to improving the pack level energy density of batteries. To achieve these objectives, it requires new designs from materials level, to single cell level, and eventually to the battery pack level. Accordingly, the team will integrate efforts in developing low-temperature electrolytes, large battery manufacturing, and thermal-runaway blocking packaging design.

Specifically, on the materials level, we aim to tackle the fundamental materials’ problems associated with lithium metal anode and high-nickel NMC or sulfur cathode, by developing advanced electrolyte systems that are compatible with both cathode and anode materials and are operational at extreme low temperature down to –60C. On the single cell level, we will carefully evaluate the cylindrical cell design by establishing an Energy density – Cycle life relationship and identify the optimal conditions that deliver the highest energy density and longest cycle life, and test under wide temperature window from –60C to 50C. Finally, we will manufacture the optimized cylindrical cells, and integrate into a fire-retardant battery pack that is ready to be equipped in a lightweight EV.

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