By Cameron Chai
CAP-XX, a company specializing in thin, prismatic supercapacitors or ultracapacitors, has designed a prototype supercapacitor module, which delivers the cranking current required to run the engine in stop-start vehicles, thus decreasing wear on the battery and avoiding the requirement of large and high-cost batteries.
The supercapacitor module delivers a peak current of up to 300 A to start the engine of a stop-start vehicle. It comprises CAP-XX's six thin supercapacitors. Its compact size facilitates its integration with the vehicle's engine bay, floorpan, or other tight spots. With an ESR of mere 4.5 mW and 150 F at 14 V, the module delivers superior power density as well as the energy required for frequent start cycles in all traffic and weather conditions. It features control electronics to steady the voltage across every supercapacitor cell, to run stop-start functions and to restrict the battery current in every restart.
The integration of the CAP-XX supercapacitor module allows the vehicle battery to be used only for continuous power functions, including navigation, lights and air conditioning, thus enabling smaller batteries or longer battery life. The battery is also used for charging the supercapacitor for its initial start. However, the supercapacitor remains charged by the alternator during driving. Moreover, the supercapacitor module will start the vehicle's engine during cold cranking, where a battery may fail to function, and stores energy with regenerative braking systems in vehicles.
In rigorous testing as per the New European Drive Cycle standard, the supercapacitor module has finished over 110,000 stop-start cycles at room temperature, while keeping the voltage of the battery above 11.8 V. Similar test results of a battery-only system showed that the battery malfunctioned within 44,000 stop-start cycles at room temperature.