According to InsideEVs, Ford Motor Company’s Advanced Battery Technical Expert Xiao Yang and Senior Manager of Energy Storage Ted Miller are set to give a talk at the SAE World Congress Experience in April, and although the exact details of their presentation are unknown, what little info is available sounds tantalizing.
InsideEVs reports that the subject of Yang’s and Miller’s talk will be rechargeable lithium-ion battery cells – and in particular, how a 5-Ah test cell was charged rapidly and depleted numerous times with no significant degradation. Ford charged the test cell from 0 to 100% SOC (State-Of-Charge) repeatedly at a rate of 16C (80 A), observing no “unexpected battery-capacity loss” after 50 test cycles. (Although, in fact, half of those cycles were to check capacity, performed at a much lower 1C charge-rate).
Now, 16C is quite a high rate. At 20C (100 A), that 5-Ah test cell can be recharged fully in just 3 minutes.
An excerpt from Yang and Miller, from the SAE website:
We try to understand the fast recharge capability of Li-ion batteries and its effect on capacity degradation. We find out that 5 Ah prismatic Li-ion cells can be fully recharged in 3 minutes under a constant rate of 20C, or in 2 min (25.5C) from 0% to 85% SOC (state of charge) without undue stresses. We cycle the battery at 16C charge rate from 0 to 100% SOC and do not see any unexpected battery capacity loss in 50 cycles, where half of the cycles are 1C-rate charge as a reference capacity check. We realize that the batteries under the fast charge study do not experience mass transport limitations in either solid electrodes or the electrolyte system.
It will be interesting to see what this means for battery longevity in electric vehicles, especially as Ford offers DC fast-charging in the revised, 2017 Ford Focus Electric and the company prepares to introduce a dozen brand-new electrified vehicles over the coming years.