Ford Focus Electric (new ~115 mile/DCFC equipped)
Ford Motor Company's Xiao Yang and Ted Miller will present an interesting paper about fast charging of lithium-ion batteries at the WCX 17: SAE World Congress Experience in April. According to a teaser about the talk, the 5-Ah laboratory sample cell revealed great charge/discharge capabilities without capacity loss. Specifically, charging takes only a few minutes "without undue stresses":
- full recharge in 3 minutes under a constant rate of 20C (100 A)
- From 0% to 85% state of charge in 2 minutes at 25.5C (127.5 A)
"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."