宝马即将在今年12月开幕的洛杉矶车展发布i8敞篷版，新车相对于现行版i8将获得很大提升。据宝马博客透露，i8敞篷版的续航里程将是轿跑车版本的一倍，而目前该车搭载了7.1千瓦时电池组，纯电动续航里程14.2英里（约合22.8公里）。不仅i8敞篷版的电池容量提升一倍（至14千瓦），而且2018款i3的电池容量也将从原来的22千瓦时提升至43.2千瓦时。新车除了续航里程增加，还将有其他提升，包括输出功率的增加。不过，现在还不清楚功率究竟能增加多少，但很可能达到400马力。其他升级包括改进底盘调校，增加新的电铜色涂装，敞篷可在车辆时速96公里时仅需14秒就可打开等等。此外，i8敞篷版和标准版车型还将对信息娱乐系统和新的辅助驾驶系统进行升级。

BMW i8 Roadster Rumored To Have Twice The Electric Range Of i8 Coupe
The upcoming BMW i8 Roadster with new soft top is to be unveiled at the 2017 Los Angeles Auto Show this December, featuring major improvements over the current i8.

According to BMWBlog, the i8 Roadster will have twice the range than i8,  which is currently rated at 14.2 miles (EPA) using a 7.1 kWh battery pack.

Doubling the battery pack size (to ~14 kWh) would indeed be a similar upgrade to the expected  bump of the BMW i3 to 43.2 kWh in 2018 (over the original 22 kWh of few years ago).

In addition to more range, comes more oompf, as the power output is to be increased. Again, at this point it is not know by how much exactly (but likely around 400 hp total).

Other news surrounds revised chassis tuning, a new Electric Copper color, and the capability to open the soft top in ~14 second at speeds of up up to 60 km/h, so a drop top on-the-fly as it were.  Overall, an upgraded infotainment system and new assistance systems are also on the list of changes for the Roadster and the traditional i8.