Implementation of a new predictive maintenance methodology for batteries. Application to railway operations

Batteries are the energy storage system most frequently used to provide backup power for emergency systems. Ensuring proper operation of these components is a basic requirement. In the specific case of railway operations, the battery´s function is of vital importance for guaranteeing passenger safety in emergency situations. A predictive maintenance method for batteries is presented which is based on measuring the internal impedance of complete modules. Knowing how this variable evolves allows us to anticipate faults and thus avoid failures and their consequences. The method described herein is particularly efficient in the case of lead-acid batteries for railway applications, because it considers the effects of the particular working environment that characterises rolling stock: ambient temperature variations, electrolyte level variations, repeated charge and discharge processes, vibrations, dirt, etc. The benefits achieved with this new maintenance method consist mainly of the optimisation of revisions in terms of quality and time, as availability and reliability are improved in a cost-efficient manner. The application of this new method to a high-demand metropolitan railway operation is presented.