Battery Package for the E-Scooter Concept from BMW Motorrad

Abstract

One of the greatest challenges in designing the electric drive train for a BEV (battery electric vehicle) lies in the balance between conflicting requirements, with a suitable, practical range on the one hand, and costs and weight on the other. As a first step, therefore, a realistic, practical range must be defined and verified. In this case, practical range is understood to be the range the scooter can achieve when used in and near the city – and not a theoretical value in constant low-speed riding mode (for example at a steady 40 km/h velocity). The actual energy needs must therefore be calculated. This is derived over four steps before the vehicle is first drafted: 1. Determining the energy consumption based on test rides: Test vehicles were fitted with data loggers, and the data from practical, customer oriented riding evaluated. 2. Simulation and calculation: The parameters relevant to the calculation of energy content needed in the simulation are drag cx*A, vehicle mass, energy recovery rate and efficiency, rolling resistance, efficiency of the entire drive train, net energy in the energy storage device, continuous/short term power and torque, and secondary consumers. 3. validating the simulations with the findings of the test rides according to NEDC [1] and WMTC [2] 4. Comparison with ISO 13064 [3]: A comparison of the practice cycles with the test cycle proposed by ISO showed that both correlated well for the energy needs required in the targeted vehicle class. The findings of all tests, measurements, simulations, and test rig runs showed that a practical range of over 100 km needs a gross energy content of at least 7 kWh. This range should be available to the customer’s vehicle also in the cold and after several years of use. The customer’s decision to buy the product is swayed very heavily by a long service life. Without doubt, the value retained by the E-Scooter from BMW Motorrad is one of the most significant development objectives.