The battery system of a multiple unit must meet the most exacting demands. High power levels need to be provided when setting off and accelerating. At the same time, however, there must be sufficient energy available to ensure an adequate range. There are also additional railway-related requirements which make it necessary to consider completely new battery technologies.
- Supplying an electric motor with energy from a battery represents a good emission-free alternative to diesel engines on lines which are not electrified and have no catenary.
- There are highly exacting demands on the reliability and quality of multiple units, as they are expected to provide more or less 24-hour service (usually on a tight schedule) for up to 30 years. The requirements placed on traction batteries are correspondingly stringent with regard to charging and discharging currents, safety, low-temperature performance, operating time and cycle stability.
- The VDE examines which of the battery technologies and cells currently available are suitable for use in multiple units, and highlights the major development trends up to 2030 and beyond.
- The exacting railway requirements can be met very well by lithium ion cells with anodes consisting of lithium titanate (LTO). However, cells of this type have relatively low energy densities. They are also expensive in comparison to the technologies used by car manufacturers.
- As an alternative to the LTO-based solution, the study draws attention to a battery technology that meets the requirements at both the battery system and cell levels.