On Condition Maintenance Based on the Impedance Measurement for Traction Batteries: Development and Industrial Implementation

Proven methods of battery diagnosis exist in the industry based on the measurement of the internal impedance from cell to cell. Nevertheless, these maintenance methodologies are incompatible with the operation of the industrial traction batteries due to great variations of ambient temperature, the paralyzation needed, and access difficulty. This paper benefits from the tested stationary standards of maintenance and includes innovative proposals in order to take into account the battery operating conditions. The difficult accessibility of industrial traction batteries finds a solution in a quicker and safer method based on the measurement of a group of cells simultaneously. This article also shows an algorithm that establishes the mathematical relation between the impedance of simultaneous cells and the temperature for any model of lead-acid battery. This algorithm is valid throughout the working temperature range of the battery. From an industrial-maintenance standpoint, the model presented can assess, at any time, the state of the acceptance and rejection of the battery modules by comparing their module impedance values. The maintenance meets the international standards for the measurement of the impedance of a group of cells under changing conditions of temperature. This new maintenance method optimizes the quality and time of the inspection process, enhancing the availability and reliability at a low cost.