An Analytical Model for Cost-Efficient Structural Materials Selection in Battery Electric Vehicles
2022-01-0266
03/29/2022
- Event
- Content
- The secular trend of automotive body structure light-weighting for internal combustion engine (ICE) vehicles is constrained by simultaneous and increasingly challenging vehicle cost, fuel economy and passenger safety standards. Mass optimization via materials selection in ICE vehicles, therefore, is ultimately dependent on the normalized cost of mass reduction solutions and the associated implications on passenger safety and vehicle performance metrics. These constraints have resulted in development and implementation of increasingly high specific-strength solutions for metallic components in the body structure and chassis. In contrast, mass optimization in battery electric vehicles is subject to alternative performance metrics to fuel efficiency, although considerations for vehicle safety and cost naturally remain directionally similar. In this study, an analytical model adapted from constrained optimization methodologies for BEV mass optimization is employed for determination of target glider mass under fixed performance requirements and packaging space. Results for cost minimization indicate an increase in total vehicle weight with increasing battery energy density and decreasing unit cost. Utilizing marginal cost functions for industrially-available automotive structural materials, it is demonstrated that the marginal cost of body materials – or the cost allowance per unit weight reduction – is accordingly reduced with fixed performance requirements, i.e., power and range, and increasingly efficient and cost-effective powertrains. The developed model further demonstrates that the reduced, although still substantial, benefit of body structure light-weighting heavily favors adoption of advanced steel solutions with current and projected BEV powertrain technologies. Materials selection considerations are then discussed with an emphasis placed on next-generation steel solutions for cost-effective occupant and battery protection.
- Citation
- Enloe, C., and Mohrbacher, H., "An Analytical Model for Cost-Efficient Structural Materials Selection in Battery Electric Vehicles," SAE Technical Paper 2022-01-0266, 2022, .