While still in some ways the forgotten child of the charging family, direct current (DC) fast charging is starting to take on some momentum. At the Electric Drive Transportation Association Annual Meeting in May, BMW and Nissan joined ABB and Fuji Electric on a panel to discuss their experiences in the United States with fast charging and what they see as the main barrier to further development of the market.
The panel addressed three technical questions that continue to hang over the DC charging market. The first question was whether the industry would ever resolve the dueling standards issue and officially adopt either the CHAdeMO standard prevalent in Japan or the SAE’s combo standard being adopted by European automakers and deployed in the United States. The clear answer from the panel was that both are here to stay. As a proponent of the CHAdeMO standard, Nissan has a head start over the combo charger supporters, having deployed over 100 CHAdeMO stations in the United States at Nissan dealerships in addition to its widespread deployments in Japan. Navigant Research’s view is that, over time, the combo charger will start to edge out CHAdeMO – simply because more automakers will adopt it. But a few markets, most notably Japan, will stick with the CHAdeMO standard, having made significant investments in deploying it.
Fast Is Better
The second question was on whether battery degradation is a concern. The consensus was that it is not. Cliff Fietzek, manager of Connected E-Mobility at BMW and David Peterson, EV Regional Manager at Nissan North America, asserted that no one is more concerned about protecting the battery than they are, and they are comfortable with the use of DC charging for their electric vehicles (EVs).
The final technical question is still open for debate: whether fast charging is more optimal at 50 kW or 20 kW to 25 kW. ABB is offering both 20 kW and 50 kW units, while Fuji has focused exclusively on the 25 kW size. Larry Butkovich, general manager of EV Systems at Fuji Electric Corporation of America, made the case for the 25 kW charger, available on the ChargePoint network in California for over a year. According to Butkovich, the average driver stops for 20 to 30 minutes and gets around a half a charge, with an average output of 18 kW. The typical fee paid is $6 to $8. Butkovich noted that usage dropped once the fees were instituted but quickly bounced back, and the company thinks a business case can be made for fast charging.
Distance versus Speed
The case for lower-power fast charging centers on the time it takes to bring a battery to 80% state of charge (SOC). BMW’s Fietzek noted that a 50 kW unit will get a 20 kWh battery to 80% SOC in 20 minutes, while a 25 kW charger takes 35 minutes. Fuji’s experience suggests that a driver will be satisfied with a 20- to 30-minute charge that doesn’t quite reach 80% SOC.
Given that the panelists cited cost as one of the biggest barriers to this market, downsizing to a less expensive 20 kW or 25 kW fast charger will make sense in applications where the charger is not expected to enable long-distance trips. The lower-power units are also less likely to trigger costly demand charges, which are another major barrier to securing more fast charging locations. These units are poised to capture more market share in the United States ‑ especially for operators not involved in deployments supported by the Department of Energy or the big automakers.