Advancements in Ni-MH batteries for high drain rate applications

Summary form only given. Saft Rechargeable Battery Systems (RBS) has been developing and enhancing battery systems for mobility applications such as electrical bikes, scooters, motor-scooters, cars and trucks. That covers the cells, the battery design, and battery intelligent electronics to monitor charge and discharge. Saft enhanced its Ni-MH technology to deliver high discharge currents of 30 A or 40 A, improved storage efficiency and improved cell design. Electrolyte composition has been improved and quantity optimized for better cycling ability. New separator provides lower internal resistance. Saft´s positive moss electrode with an innovative treatment limits irreversible loss of capacity. The negative electrodes with the edge welding process, combined with high power inner connections, both provide the high current capability for demanding mobility applications. On the battery design sided an efficient pack design, inter cell connections, wiring, proper cooling if required, are also key in delivering high performances. Efficient battery monitoring is crucial when dealing, for instance, with 30 cell batteries, or even more, to avoid cell reversal during discharge, to terminate discharge at the right voltage, to change from one charging mode to another using the right temperature gradient with added cut off backups. It´s key also to manage the different charging steps to optimize battery performances and cycle life. Saft´s proprietary Intelligent Battery Monitoring System (IBMS) provides all these functions, requiring then only a basic charger