eVia – Electric Vehicle System
Electric propulsion is currently not up to the level of development it needs to be to effectively power vehicles. The batteries of today have adequate power output for transportation applications, but the energy density associated with such units is simply not comparable to internal combustion engines. This means that while a battery can provide, for example, good acceleration for a car, that same car will not be able to go very far on one charge. The eVia system aims to solve this problem by integrating a Stratum lithium-ion polymer battery with a Swift fuel cell stack. The battery supplies the power, while the fuel cell stack supplies endurance as a range extender. The above picture details a simplistic systems diagram of the proposed eVia project.
Note that both reactants have a loop whereby they travel from a higher concentration stock tank, into a dilution tank, move into the fuel cell stack and then the reactants either get filtered out or make another pass in the loop. The purpose of the dilution tank is to take higher concentration reactants and dilute them as necessary to keep a roughly steady state concentration in the loop. As more reactants are needed to keep the concentration up, more stock solution is fed into the system. This allows for more energy to be stored without the necessary water weight and volume to keep it at a standard concentration. On the H2O2 side, water is collected and used for dilution. The proton fuel (for example urea) is pumped countercurrently to the oxidizer on the other side of the membrane. The fuel cell stack’s purpose is to create power for the motor during low power applications, any residual energy being used to charge the battery. To show how effective this system potentially can be, we have put together a mathematical model with a Stemme S10. This case study shows the basic feasibility of the eVia system, in particularly with regard to how much range the aircraft can have with it.