24.2.2014Advanced polymer battery for Soul EV
The forthcoming Kia Soul EV is to come with a class-leading battery energy density of 200 Wh/kg as a result of a three-year joint development programme between Kia Motors Corporation and SK Innovation in Korea.
Kia engineers have developed a power pack featuring 192 lithium-ion polymer battery cells in eight modules, delivering a total battery capacity of 27 kWh. The pack incorporates state-of-the-art thermal control technology to maintain individual cells at optimum temperature and structural design to enhance crash worthiness.
The advantages of a lithium-ion polymer battery – over normal lithium-ion batteries – include: greater efficiency due to the simple cell structure (fewer parts), lower costs, increased safety and reliability (thanks to better thermal diffusion and internal pressure control), ease of manufacture in a variety of capacities and shapes.
Nickel-rich NCM (nickel-cobalt-manganese) cathode material is used in the mass production of the battery cells for Soul EV. Energy density, which is dependent on cathode capabilities, is a core performance factor deciding EV driving range. By exploiting the class-leading energy density of its battery, the Kia Soul EV will have an official test driving range of around 200 km (124 miles) on a single charge.
High performance electrolyte additive and anode materials were also developed to meet various performance requirements, such as safety and lifecycle, while maintaining high energy density.
In addition, a special secure separator is used in the Kia Soul EV's battery cells. The separator determines the safety and the charge/discharge speed of the battery. It has improved thermal resistance, which helps to keep the cell secure from exposure to heat or fire by preventing the shrinking of the separator if the temperature of the cell increases beyond normal levels.
Together, the low electrical resistance battery cell, proper battery system thermal control and accurate state-of-charge calculation improve the charging performance, thereby enabling a rapid charge time of 25 minutes (100 kW DC) or 33 minutes (50 kW DC). A fast charge takes up to five hours (6.6 kW AC).
The Kia Soul EV had its global debut at the 2014 Chicago Auto Show on 6 February and will have its European debut at the 2014 Geneva Motor Show on 4 March. The vehicle is expected to go on sale in European markets, including the UK, in the autumn.