Fast Charging Li-ion batteries developed by Penn State Researchers

[G. David Felt]

Penn State Research

Penn State Nickel foil fast charging battery diagram

To quote their abstract with significance:

Significance

Range anxiety is a key reason that consumers are reluctant to embrace electric vehicles (EVs). To be truly competitive with gasoline vehicles, EVs should allow drivers to recharge quickly anywhere in any weather, like refueling gasoline cars. However, none of today’s EVs allow fast charging in cold or even cool temperatures due to the risk of lithium plating, the formation of metallic lithium that drastically reduces battery life and even results in safety hazards. Here, we present an approach that enables 15-min fast charging of Li-ion batteries in any temperatures (even at −50 °C) while still preserving remarkable cycle life (4,500 cycles, equivalent to >12 y and >280,000 miles of EV lifetime), thus making EVs truly weather-independent.

Abstract

Fast charging is a key enabler of mainstream adoption of electric vehicles (EVs). None of today’s EVs can withstand fast charging in cold or even cool temperatures due to the risk of lithium plating. Efforts to enable fast charging are hampered by the trade-off nature of a lithium-ion battery: Improving low-temperature fast charging capability usually comes with sacrificing cell durability. Here, we present a controllable cell structure to break this trade-off and enable lithium plating-free (LPF) fast charging. Further, the LPF cell gives rise to a unified charging practice independent of ambient temperature, offering a platform for the development of battery materials without temperature restrictions. We demonstrate a 9.5 Ah 170 Wh/kg LPF cell that can be charged to 80% state of charge in 15 min even at −50 °C (beyond cell operation limit). Further, the LPF cell sustains 4,500 cycles of 3.5-C charging in 0 °C with <20% capacity loss, which is a 90× boost of life compared with a baseline conventional cell, and equivalent to >12 y and >280,000 miles of EV lifetime under this extreme usage condition, i.e., 3.5-C or 15-min fast charging at freezing temperatures.

According to another site, this new design only adds a 0.5% weight and a 0.04% to the cost while adding a breakthrough that frees battery design from other tradeoffs till such time that solid state batteries become practical in production and cost. The biggest challenge that this helps solve is what has been called the Goldilocks zone. Cooling is important but so is heating of a battery so that it is in that perfect optimized temperature to accept the maximum charging into the battery cell. Currently OEMs are using either air or liquid to get the just right zone of charging for their auto battery.

Between solid state breakthroughs and continued research such as this, one could see much faster charging times and longer ranges in all weather conditions to getting an EV running all over regardless of what mother nature throws at it.

Green car Report

Charged EVS Goldilocks Story